tfetatj} of tionptM. 




UNITED STATES OF AMERICA. 



RITCHIE'S 



CATALOGUE 



OF 



SCHOOL APPARATUS. 




E. S. RITCHIE <fc SONS, 

Mb. 149 TKEMOWT STKEET, 

BOSTON. 

1869. 






RITCHIE'S 



*7*-^ 



ILLUSTRATED CATALOGUE 



OF 



SCHOOL APPARATUS 




V 

BOSTON: 

14,9 TREMONT STREET. 

1869. 




RITCHIE'S ROTARY AIR PUMP. 



Entered, according to act of Congress, in the year 1869, by 

E. S. RITCHIE & SONS, 

In the clerk's office of the District Court for the District of Massachusetts. 



• 



n 



Advertisement. 



Terms, Cash. No discount or deviation can be made 
from Catalogue prices ; and those who favor us with or- 
ders by mail may rely on receiving instruments as good 
in quality, and at the same price, as if they came per- 
sonally. 

We have no Agents, nor are our Instruments for 
sale by any others. We fix our, prices as low as we can 
afford for the quality of our work, and leave no margin 
for discounts to those who buy to sell again. We wish, 
also, that our instruments be received by the purchaser 
in perfect order. 

Drafts at sight, to our order, on New York or Phila- 
delphia, received at par ; for small sums, post office money 
orders are convenient. 

A charge of two per cent, for boxing, packing, and 
delivery at railroad station will be added to the bill. 

We will deliver free of freight to the nearest railroad 
station, and insure against loss and breakage by trans- 
portation to any purchaser, either of the sets, or a similar 
selection from this Catalogue, provided that a draft is 
received previous to shipment of order, and that the 
amount is not less than one hundred dollars. 

For testimonials from the highest sources, to the qual- 
ity of our work, and for our responsibility, we refer to 
letters at the close of Catalogue. 

Great care will be used in packing, but unless we 
insure, our responsibility must end with delivery to the 
public carrier. Our charge for insurance for average risk 
is two and a half per cent. 



EITCHIE'S CATALOGUE OF 

fcilesopjiral Instruments, 

WILL BE SENT ON APPLICATION. 



PREFACE 



The following Catalogue has been prepared of Appa- 
ratus especially adapted for the requirements of the Gram- 
mar and High Schools of the country. It has chiefly 
been compiled from our Catalogue of Philosophical In- 
struments, with some new instruments which we have 
devised and constructed for the purpose. 

The aim has been to select articles that each will illus- 
trate a Principle in the simplest and clearest manner ; to 
adopt the size best uniting efficiency with economy ; to 
avoid multiplying experiments illustrating the same prin- 
ciple ; and to omit such as are beyond the intended 
range. 

The instruments enumerated in this Catalogue are 
almost exclusively of our own manufacture. We shall 
adhere strictly to our rule, that everything shall be thor- 
oughly well made and finished, of best materials, and 
carefully adjusted ; and every article is warranted to be 
so, and to correspond to the description. 

Particular care is given to the lacquering, which is 
done in a manner that will resist the action of the atmos- 
phere, and bear use and handling for a long time untar- 
nished. 

E. S. EITCHIE & SONS. 



Edwakd S. Ritchie. 
Thomas P. Ritchie. 
John Ritchie. 



(iv) 



RITCHIE'S 



CATALOGUE 



SCHOOL APPARATUS 



LAWS OF MATTER AND MECHANICS, 





No. 1. 



No. 2. 






ddqadO 



No. 3. 




No. Price. 

1. Adhesion Plates; a pair of ground glass plates, with handles, $1.25 

2. Lead Hemispheres, for adhesion. Scrape the surfaces bright, and press 

them firmly together, at the same time moving one slightly on the other, 1.00 

3. Inertia Apparatus ; stand, with spring and ball, 1.75 

4. Capillary Tubes ; a set of six glass tubes of different calibre, in a box, . . .50 

5. Capillary Tubes ; six tubes sealed into a bar to rest upon a tumbler, . . 1.00 

6. Capillary Plates ; of plate glass with elastic band. Separate them at one 

edge slightly, and set them upright in a plate of water, 1.50 

7. Collision Balls ; a base and pillar, with a frame sustaining five lignum-vitae 

balls with double cords, 6.50 

8. Collision Balls ; a set of five lignum-vitae balls, V/^ inch diameter, suspended 

upon a metallic bar which is fitted to attach to the pillar of the set of Me- 
chanical Powers, (see cut No. 12,) <- 3.50 



SCHOOL APPARATUS 






No. Price. 

9. Centre of Gravity ; a set of illustrations of centre of gravity, viz. : 

1st. Triangular block, with holes drilled at the angles, from which lines are 
drawn, representing the verticals through the several points of sup- 
port and the common centre of gravity. 

2d. A square block, with similar centres and lines. 

3d. An oblique parallelogram, with centres and lines. 

4th. Two balls of unequal size, with centre in the connecting rod. 
A handle, with steel pin for the above. 

5th. Plumb line. 

6th. Loaded wheel and stand ; a disk of wood which has a mass of lead in- 
laid near one edge, with centres of magnitude and gravity. 

7th. Leaning tower, with movable capital and inclined base ; with the capital 
removed, the vertical of the centre of gravity falls within the base ; 
replace the capital, and the vertical falls beyond the base, conse- 
quently the tower falls ; the centres are drilled to balance upon the 
stand of 6th illustration. 

8th. Double cone and inclined plane ; the cone rolls up the inclined plane, 
the bars of which diverge so that the axis of the cone actually 
descends. 

9th. Horse and rider, with lead ball and stand ; adjusted to balance on the 

legs of the horse 10.00 

10. Centre of Gravity. A set of illustrations selected from No. 9. 

1st. Triangular block. 6th. Loaded wheel. 

3d. Oblique parallelogram. 7th. Leaning tower. 

4th. Balls and rod. 8th. A handle for 4th and 6th. . . 5.00 



LAWS OF MATTER, AC. 




No. 11. 

^"o. Price. 

11. Illustration of Pulleys, and Wheel and. Axle. A mahogany base 

and pillar, with a screw and nut to confine a bar with hooks for the 
following systems ; the pulleys are of brass ; in the double ones the 
wheels are separated by partitions ; all the systems are balanced. 

1st. Fixed pulley and cord; power and weight equal. 

2d. Fixed and movable pulleys, power and weight as 1 to 2. 

3d. Double movable pulleys, power and weight as 1 to 4. "With the pul- 
leys, the :; system of four single pulleys -"' can be made, and cords fit- 
ted and sent with the set; power and weight as 1 to 2, 4. or S. 

4th. Wheel and axle, with four diameters, and cords, suspended in a 
frame to attach to the pillar. 

5th. Ship's capstan and levers: a hook is placed in the basement to se- 
cure a fixed pulley; pass the cord over a pulley on the bar. 

6th. Cords fitted for making the " system of four single pulleys,'-' by 
using those of the above sets, 

7th. A set of weights from 1 to 32 ounces . 20.00 

12. Simple and Compound Levers. Mahogany base and pillars: the 

levers are balanced by a riding weight 5.50 

13. "Wedge. Inclined Plane, and Screw. Inclined plane and car. the 

cord passes over a pulley for the weight ; screw in frame, with lever ; 
wedge: all of mahogany 7.50 

14. Set of Mechanical Powers, including ZS'os. 11, 12, 13 33.00 

2s"OTE. — This arrangement for the illustration of the simple machines 
will be found very convenient and complete. The teacher can thus 
have before his class those only that illustrate the lesson, which he 
can show in a conspicuous manner. 



SCHOOL APPAEATUS. 




No. 15. 





No. 16. 



No. 17. 



No. Price. 

15. Illustration of Pulleys; polished mahogany base, pillars and bar, sup- 

porting the four following systems of pulleys, wheel and axle, and 
capstan. The pulleys are large, with improved straps, with divis 
ions, strung with silk cord and balanced. 

1st. Fixed Pulley and cord; power and weight equal. 

2d. Fixed and Movable Pulleys, power and weight as 1 to 2. 

3d. Double Fixed and Movable Pulleys, power and weight as 1 to 4. 

4th. System of four Single Pulleys, power and weight as 1 to 2, 4 or 8. 

5th. Wheel and Axle, with four diameters, and cords. 

6th. Capstan and Levers. 

A set of brass weights from one to thirty-two ounces 35.00 

16. Lever Balance and Steelyard; base and brass pillar, mahogany beam 

with steel knife edges, and hooks for weights 10.00 

17- Illustration of the Wedge ; mahogany frame, brass wedge, with fric- 
tion rollers ; the upper bar and roller are balanced ; a pulley and cord 
for the power; the length of the wedges is to the height as 4 to 1. . . 7.50 



LAWS OF MATTER, &C 





Xo. 18. 



Xo. 19 A. 



No. Price. 

18. Central Forces ; a hoary metal stand and spindle, on which revolves an 

elastic ring", with a spool attached for a cord to be wound upon; the ring 
in rapid motion assumes the form of the dotted line in consequence of 
the centrifugal force ; the spring of the metal tending to counteract this 
force represents the centripetal force, . . . . S3. 75 

19. Gyroscope ; a brass ring or wheel upon an axis, supported by a ring with 

ears to rest upon a point and stand ; the motion of this instrument is 
the resultant of the force of inertia, by which revolving bodies tend to 
remain in the same plane, combined with the force of gravity : theb 
two forces produce a horizontal motion around the point of support. 
Curiosity is excited by the motion of this instrument, because it does 
not fall ; the force of gravity united with another force, which is not 
apparent, changes the motion to another direction. This instrument 

is hardly suitable for illustration in schools, 3.50 

19 A. Parallelogram of Forces ; a light graduated frame with hinged joints; 
two of the pulleys of Xo. 12 should be fixed to the blackboard, three 
or four feet apart; the cords from two of the bars pass through these 
pulleys to weights, which represent the direction and intensity of two 
forces acting on the point of attachment ; the longer bar is graduated 
below the hinge to equal parts. A third bar, hinged at the same point, 
represents the direction, and a weight attached the intensity of the 
resultant force ; this bar is graduated to the same scale ; a fourth grad- 
uated bar is attached to the third, and is suspended so as to be always 
parallel to the shorter of the first pair. The readings of the gradu- 
ated bars will always correspond to the intensity of the forces, and 
the enclosed space forms the triangle of forces from which the paral- 
lelogram can be drawn 7.50 

19 b. Illustration of the Pendulum, a bar to attach to the pillar of Xo. 12. 
Two pendulums of equal length, with balls of lead and boxwood, 
which oscillate in the same time, showing that this is not affected by 
the length of the arc of vibration, nor by the weight or density of the 
ball : two other pendulums, of one fourth and one ninth the propor- 
tional length, which oscillate in one half and one third the time, prov- 
ing that the time of a pendulum is as the square root of the length. . 3.50 



10 



SCHOOL APPARATUS. 



HYDROSTATICS, 

fife 





No. 25. 





No. 2(5. 



No. 27. 



No. 
20. 



21. 



22. 



23. 



24. 
25. 



26. 



27- 



Price. 

Equilibrium Tubes, or hydrostatic paradox ; four glass vessels of dif- 
ferent forms, connected by a tube within the base, showing- that a liquid 

preserves a level. 3.50 

Note. — Pour into one of the tubes enough of alcohol to fill it, displa- 
cing the water ; the column of alcohol will stand as much higher as its 
specific .gravity is less. 

Bottle and Tubes. A closed jar with three tubes, opening upward, 
downward, and laterally, to show that the pressure is equal in each di- 
rection at same depth. 3.50 

Glass Cylinder and Plate, to illustrate the upward pressure of liquids ; 
the tube is ground to fit the heavy brass plate; hold the plate up by the 
string, and plunge the cylinder in water; the pressure below will then 
sustain it 3.00 

Liquid Adhesion Plate. A glass disk with cord; considerable force 
is required to lift it from the surface of water; the water below the 
plate will be raised considerably above the level in the vessel 1.50 

Siphon of glass tube 50 

Tantalus Cup, illustrating intermitting springs; fill the cup slowly; 
when the water rises to the bend of the siphon, it will flow and empty 
the cup 2.00 

Glass Balloon and Car, in jar; the balloon is partly filled with water; 
by pressing down the elastic cover, the air above the water is com- 
pressed, and transmits a pressure to the water, by which the air in the 
balloon is also compressed, and more water is forced in through an ori- 
fice, increasing its weight so that it sinks; remove the hand, the air 
within the balloon expands, water is expelled, and the balloon rises. 
This simple apparatus strikingly illustrates the compressibility and 
elasticity of the air, and the principles of specific gravity 5.00 

Model of Lifting Pump. A strong glass cylinder with brass caps, 

showing the action of the piston aud valves 9.00 



HYDROSTATICS. 



11 





No. 28. 



No. 29. 



28. 



29. 



30. 

31. 
32. 
33. 
34. 



35. 



36. 
37. 



Model of Lifting and Force Pumps. Lifting and force pumps on a 
mahogany stand, with large cistern. 
The cylinder of the lifting pump is of glass, showing clearly the piston 
and valves ; a funnel and tube conveys the water again to the cistern. 
The force pump is also of glass, with glass air-chamber; the piston 
and both valves are visible in action ; the condensing-chamber has a 

stopcock and hose, with jet 22.50 

Archimedes' Principle. A brass cylindrical cup, with a bail and hook 
beneath; a cylinder of brass exactly filling the cup; and counter- 
poise; suspend the cup with the cylinder enclosed and counterpoise to 
balance of No. 56 ; then suspend the cylinder by a thread to the hook, 
and let it be immersed in a tumbler of water, and fill the cup with wa- 
ter; it will again be balanced by the counterpoise, proving the buoy- 
ancy of a liquid to equal the weight of the same volume 2.50 

Model of "Water Wheels, overshot, undershot, and breast wheels, 

with water-course neatly made of tin, and painted 12.00 

Hydrometers. Baurae's scale for spirit, acids, milk, syrup, &c; 1.25 and 1.00 

Hydrometer, universal, with O in the middle of the scale 2.50 

Hydrometer, Nicholson's, for specific gravity of solids 6.00 

Ritchie's Illustration of the Hydrostatic Press. A frame of brass ; 
within the base is placed a cylindrical, bellows formed bag of rubber, 
connected by a tube to a rubber globe, fitted with a cap ; a cylinder of 
iron, 2>£ inches diameter and 4 inches high, rests upon the bag. Fill 
the globe with water, close the cap, and elevate the globe of water; 
the hydrostatic pressure of the column of water will force it into the 
bag, raising the iron cylinder; depress the globe, the weight will force 

the water back into the globe 9.00 

Specific Gravity Balance. A brass beam and scale-pans, brass stand- 
ard and base 1.00 

Model of Barker's Mill. Metal tube, and funnel to attach to No. 65. . 1.25 
Hero's Fountain. 24 inches high, with jet 8.00 



12 



SCHOOL APPARATUS 



PNEUMATICS. 




No. 40. 



No. Price. 

40. Ritchie's School Air Pump. The plate is eight inches diameter, and 

forms the top of a cylinder four inches high, which prevents any flex- 
ure or change in its form. The pump cylinder is placed horizontally 
beneath the plate, passing through its cylinder which protects it from 
injury. The inlet tube from the plate into the pump is of large diam- 
eter, and opens into the cylinder below the piston when fully drawn 
out, allowing a free communication from the receiver to the pump, 
without valve or obstruction. The piston is of a new construction, 
and is packed so as to move freely, yet is perfectly tight, and will wear 
a long time uninjured; the exit valve is simply a disc of oiled silk, 
held in place by a pin in the middle, and covered by a brass dome; the 
valve can be changed if required, in a minute's time. The exit valve 
tube passes to a cistern below. The base is of mahogany, and is fur- 
nished with a table clamp screw. 
This pump is essentially automatic in its action, and will produce a vac- 
uum more than twice as high as any pump in which the valves are 
raised by the air ; this is of great importance in all experiments of 
electricity in vacuum. It is worked with ease, and is warranted to be 
trustworthy and durable. A patent has been applied for 25.00 

41. Ritchie's Patent Air Pump, with automatic action. The form of the 

pump is similar to No. 42 (see Cut on page 14), with base, pillar and 
lever; the plate is 12 inches in diameter; cylinder 7)4 inches by 2>£ 
in diameter; a full description of the construction and the operation 
of the piston and valves, with cuts, is given on the next page. The 
friction of the piston is very slight, and the pump is worked with 
great ease, while the rarefaction obtained is higher than has been 

reached by any other pump 100.00 

Notk. — In our larger catalogue will be found a description of a large 
pump, with rotary action. See Cut on page 2. 



PNEUMATICS 



13 





Fig. A. 




DESCRIPTION OF RITCHIE'S PATENT AIR PUMP. 

Fig, A is a section showing the valves, &c, much exaggerated, for distinctness. 

The lower valve is conical, held in place by a triangular stem fitting the tube; it is 
raised by the valve-rod passing up through a stuffing-box in the piston ; an enlarged 
section (fig. b.) shows the manner in which the attachment is made, which allows a 
motion of the rod sidewise. so that any slight change of form of the packing of the 
piston, or stuffing of the rod, cannot prevent the valve from shutting properly. The 
cone of the valve is ground to a perfect fit to its seat, but the valve is also furnished 
with a disk of oiled silk which projects just beyond its outer edge, and touches the flat 
surface of the valve seat; the valve-rod extends up, and its upper end is secured in 
a hole drilled in the upper plate, of depth to allow motion to open the valve. 

The piston is of thick brass, made in two parts ; the upper piece has a hole drilled 
larger than the piston rod; the lower part of conical form, ground to fit a cone on the 
piston-rod ; this forms the piston-valve. The lower piece of the piston covers the 
end of the piston-rod, but allows it enough motion to open the valve; a series of small 
holes through the plate gives a free passage for the air to the valve. 

A third valve is placed outside the cylinder, made of oiled silk in the usual way. 

In the thickness of the upper plate of the cylinder is inserted a steel lever, one end 
of which covers the valve-rod; the other end, when the lower valve is closed, is flush 
with the plate; but when the valve is raised, it projects into the cylinder. 

In action, the first motion upward of the piston-rod closes the piston-valve; the 
first motion of the piston opens the lower valve; as the piston ascends, the air above 
it is forced out through the upper valve; and air from the receiver flows unobstruct- 
edly into the cylinder. The piston strikes the tail of the lever, and at the instant of 
arriving at the top, closes the lower valve. The first downward motion of the piston- 
rod opens the piston-valve, and the small quantity of air remaining in the interstices 
above the piston is distributed throughout the cylinder, but none can flow into the 
Receiver , when the piston reaches the bottom, the interstices below contain air as 
rarefied as an ordinary pump can exhaust ; the next upward stroke must leave al- 
most a perfect vacuum below; and as there is no obstruction to the receiver, it must 
by continued action be brought to the same degree of exhaustion. The working parts 
are very substantial, not likely to be deranged, and are readily accessible. 

The result is, that almost a Torricellian vacuum is obtained ; a true mercury gauge 
can be brought to within one fiftieth of an inch. The Aurora T"be with the discharge 
of an Induction Coil, or Holtz machine, is filled with brilliant stratified light. 



14 



SCHOOL APPARATUS* 




No; 42. 



No. Price. 

42. Air Pump, of Ritchie's improved construction, on Leslie's principle, with 

lever, and closed cylinder, by which the pressure of the atmosphere 
is in a great degree removed from the piston. The cylinder is highly 
polished; the piston rod passes through a stuffing box of cup form, 
which is to be half filled with oil; the outer valve is of original con- 
struction, similar to the one adopted in No. 40. The dome, covering 
the valve as well as the cylinder head, can be readily unscrewed by 
the hands. The exit tube passes from a channel round the valve 
through the base into a cistern, to receive any oil that may pass over. 
Oil cannot accumulate upon the valve as in the old form. The base 
is 20 by 14 inches, cylinder 7)£ by two inches, plate 8 inches in di- 
ameter 45.00 

43. Swelled Receivers. One gallon, 2.50; two gallons, 3.50 

44. Plain Receiver {See cut No. 40). Quart, 1.00; two quarts, 1.25; gallon, . 2.00 

45. Sliding Rod Receiver (See cut No. 42). One gallon receiver, with brass 

cap and sliding rod, complete 5.00 

46. Cylindrical Jar to place under receiver; two quarts 1.50 

47. Hand Glass, or Bladder Glass, ground at each end; place it upon the 

pump, and cover the opening with the palm of the hand ; it will be 
forced down with a pressure of about forty pounds if the glass is 
entirely exhausted. Stretch a piece of thin wet bladder over the largo 
end, tie it tightly, and let it dry; put the small end on the plate, the 
bladder will burst with a loud report; or tie over a piece of vulcanized 
rubber, it will be forced in by atmospheric pressure until it nearly fills 
the interior of the glass 1.25 

48. Ritchie's Improved Condenser; the cylinder is 7 by l l 4 inches; 

the base cap can be unscrewed by the hand ; a large screw in the thick- 
ness of the cap holds the inlet valve by its flange, while the exit valve 
is secured at its lower end by a pin. The valves are thus protected 
from injury, yet both are readily accessible; both are of oiled silk, and 
hold perfectly tight. (See Fig. c, page 13.) 9.50 



PNEUMATICS, 



15 




No. 50. 





No. 48. 



No. 49. 



No. 53. 



No. 54. 



No. 
49. 



50. 



51. 



52. 



53. 



54. 



55. 



56. 



57. 



58. 



Price 

Condensing Chamber, of heavy copper, with stopcock, movable inte- 
rior tube, and water-jet 8.50 

Mercury Tunnel, or Mercury Shower; a cup of mahogany with a cyl- 
inder of porous wood ; place upon the hand glass with a tumbler be- 
low ; pour some mercury in the cup ; exhaust, and the atmospheric 
pressure will force the mercury through the pores of the wood. ... 1.25 

Expansion Bolt Head, and vial; half fill the vial with water colored 
with litmus or red ink; place under the receiver; the air in the globe 
wilf expand, and rush out through the water ; then vent the pump and 
the water will nearly fill the bulb 75 

Freezing Apparatus; receiver, pan for acid, improved silvered water 
cup, and supporting frame. Pour a little sulphuric acid into the pan, 
and a little water into the cup ; the water will be frozen by the rapid 
evaporation 4.00 

Bacchus Illustration; two glass jars, a brass tube passes from the 
bottom of one, fitting air-tight to its brass oup, and passes over to the 
bottom of the other jar. Nearly fill the closed jar with colored water, 
place under the receiver; the confined air in the first jar will expand 
and drive the water over into the other jar; then vent the pump and 
the water will be driven back again 2.75 

Magdeburg Hemispheres, 4}/, inches diameter; stopcock, handles, and 
stand; screw the stopcock into the pump plate, exhaust, close the 
stopcock, and screw on the opposite handle; great force will now bo 
required to separate the hemispheres 7.50 

Rubber Bag and Cap. Put the bag, with very little air in it, under 

the receiver; the confined air will expand and distend the bag 2.25 

Weight and Buoyancy of Air (See cut, No. 40). Brass balance, with 
brass support and stand; globe of three inches diameter, with stop- 
cock, hook, and counterpoise 7.50 

"Water Hammer ; a glass tube containing water in a vacuum, hermet- 
ically sealed ; the water strikes with a metallic concussion 1.25 

Barometer Tube. A thick tube 33 inches long, closed at one end; fill 
with mercury, close it tightly with the finger, and plunge it under mer- 
cury in a cup ; remove the finger and the mercury column will fall a 
little, but will remain nearly 30 inches high in the tube . 1.50 



16 



SCHOOL APPARATUS, 




No. 59. 



No. 60. 



No. 61. 



No. 63. 



No. 
59. 



60. 



61. 



62. 
63. 



64. 



65. 



66. 

67. 

68. 
69. 



Price. 

Barometer Apparatus of improved construction. Receiver 33 inches 
high; a glass tube with brass screw collar fitted to a mercury cistern; 
the top of the cistern has a cap and oiled silk valve ; exhaust and the 
air will pass out freely through the valve; admit the air and the mer- 
cury will rise to near the barometer height 6.00 

Fountain, a heavy glass receiver 15 inches high, with cap and stopcock; 
a long brass jet and stand ; exhaust the bell and plunge the stopcock 
in water, which will be forced up in a jet 6.50 

Upward Pressure Apparatus. A glass cylinder supported upon a tri- 
pod stand, with piston and strap for weight ; the top of the cylinder is 
closed by a plate, which is to be connected to the air-pump by the hose 
No. 62. Exhaust, and the piston will be forced up by the atmospheric 

pressure 11.00 

Note. — The upward and lateral pressure of the air is as strikingly 
illustrated by the Magdeburg hemispheres. 

Rubber Hose, with brass screws to connect No. 61 to air-pump 3.00 

Guinea and Feather Tube. A heavy glass tube with brass caps, stop- 
cock, and stand; a thin disk of metal and several of tissue paper are 
enclosed ; exhaust, and then elevate alternately each end of the tube ; 
the tissue paper disks will fall as rapidly as the metal one. The tube 
is fitted with a point for an Aurora Tube. (See No. 131.) 8.00 

Air Gun ; a brass tube with socket to fit a stopcock, to be used with the 
condensing chamber, with balls; drop a ball into the tube, quickly 
turn the stopcock half round, enough air will escape to throw out the 
ball with great force 1.25 

Revolving Jet, with screw to attach to the Condensing Chamber. "When 
used as a Barker's Mill, leave off the interior tube, and invert it with- 
in the jar No. 46 2.25 

"Wood Cylinder and Weight, to sink when the air is removed from 

the pores of the wood 25 

Plate Paradox. A brass plate and tube, and mica disk; lay a disk upon 

the plate, and it cannot be blown off 75 

Washers for stopcocks, &c .25 

Oil to use with air pump „..„.<,„.. .25 



HEAT. 



17 



HEAT 




No. 70 



No. 71. 






No. 77. 



No. 75. 



No. 76. 



No. 
70. 



71. 



72. 



73. 



74. 



75. 



76. 



77. 



78. 



Price. 

Palm Glass. Two bulbs and connecting tube, containing 1 ether in a vac- 
uum, which boils by the heat of the hand. The absorption of heat in 
vaporizing- a portion of the ether will be sensibly felt ; the bulb in the 
hand will feel cold 1.00 

Pulse Glass. Similar to No. 70, but with one bulb; the other end is cy- 
lindrical; the heat of each pulsation in the hand is marked by a bub- 
ble formed in the tube 1.00 

Bing and Ball, showing the expansion of metals by heat; the ball, 
when cold, passes freely through the ring; heat the ball over a spirit 
lamp, and it will not enter the ring • 2.25 

Bar and Gauge, with handles like No. 72; the bar, when of same tem- 
perature with the gauge exactly fits it ; by warming the bar (or by ex- 
posing the gauge to cold), it will not enter. This apparatus is more 
sensitive, and better than No. 72 . 2.25 

Compound Bar, showing the unequal expansion of different metals; a 
bar of iron and brass riveted together; heat the bar, and it becomes 
curved by the greater expansion of the brass; 1.25 and 2.25 

Fire Syringe and Tinder ; showing the heat evolved by the sudden 
compression of air; a brass cylinder and piston, with a cavity for tin- 
der; force the piston down suddenly, and the tinder will be fired. . . 3.00 

Beflectors and Ball. A pair of polished, silver plated concave reflect- 
ors, in a case Avhich is divided in such manner as to form a stand for 
each; an iron ball with stand; heat the ball to a red heat, and place 
it in focus of one mirror, and place one bulb of No. 70 or No. 85 ten or 
twenty feet distant, in the focus of the opposite mirror, showing that 
heat is reflected in the same manner as light ,- 12.50 and 9.00 

Wollaston's Steam Engine. A cylinder with a thin copper globe, 
piston and rod, and handle ; pour a little water into the globe, and hold 
it over a spirit lamp ; steam will be generated and drive up the pis- 
ton ; then plunge the globe in cold water ; the steam will be condensed 
and the piston forced down by atmospheric pressure. This is jl sim- 
ple but beautiful illustration of the low-pressure engine 5.50 

Wire Gauze, in frame, for experiments with flame, illustrating the Davy 

miner's lamp .75 



18 



CHOOL APPARATUS 




No. 90. 



No. 

79. 



80. 



81. 



83. 

84. 
85. 
86. 



87. 



88. 



89. 
90. 



Price 
Specific Heat. Two balls of copper and tin of equal weight; pour into 
two thin tumblers the same weight of water, and note the tempera- 
ture by a thermometer; plunge the balls into boiling water, and then 
one in each of the tumblers. It will be found that the copper ball has 
raised the temperature highest, but that in neither is the water raised 
as many degrees as the balls have lost, showing that copper has more 

capacity for heat than tin, but less than water 1.75 

Plates for Radiation and Absorption. Two plates, one bright the 
other black, with stand. Heat the copper ball of No. 79, place it mid- 
way between the bulbs of No. 85, and let the plates touch the bulbs; 
the black will prove to be the best absorber. Place the plates in con- 
tact with the ball, and the black will be the best radiator 1.50 

Cell for Iodine. For solution of iodine in bisulphide of carbon : this 
solution has the property of cutting off totally all heat from a lumi- 
nous source, while it permits obscure heat to pass freely 5.50 

Principle of Ventilation. A glass bell, with a tube or chimney, and 
movable diaphragm ; place a short piece of a lighted candle within 
the bell, it will soon be extinguished; put the diaphragm into the 
tube, a circulation takes place, and the candle will burn brightly. . . 3.50 

Thermometer in japanned case; six inch, .75; eight inch, 1.00 

Thermometer for liquids 1.25 

Differential Thermometer, Leslie's, on stand, 3.50 

Conductometer. Brass plate on tripod, six rods of iron, brass, tin, cop 
per lead and glass; place it over a spirit lamp with phosphorus upon 

the ends of the rods 4.50 

Eolipile. A ball and jet ; heat it over a spirit lamp, plunge it under wa- 
ter so that water will be forced in ; heat until the steam issues with 
force ; substitute ether and the jet will burn with a beautiful flame. . 3.50 
Pyrometer. Mahogany frame, with dial and adjusting screw; rods of 

iron and brass, and two small spirit lamps 7.50 

Psychrometer, or Mason's Hygrometer, with fountain in boxwood scale. 4.00 
Hygrodeik (Edson's); a very valuable and convenient adaptation of a 
scale to the Psychrometer, by which all calculations from the formula 
are saved, and the results obtained at a glance. Viz. : — 1st. The 
actual and sensible heat of the room. 2d. The relative amount of 
moisture in the air on a scale of 100 degrees, zero being absolute dry- 
ness, and 100° saturation for the given temperature. 3d. The dew- 
point. 4th. The weight of water in grains present in each cubic foot 
of air. 5th. The force of vapor. By following the indications of this 
instrument, not only health and comfort will be promoted, but also 
economy in the saving of fuel 15.00 



ELECTRICITY. 



19 



ELECTRICITY 




:^s 



RITCHIE'S PATENT HOLTZ MACHINE. 

One of the most remarkable inventions of late years is that of the Holtz Machine, 
which is an instrument for the excitement of electricity on a principle analogous to 
a revolving- Electrophorus, which was the aim of the inventor whose name it bears. 

The construction and arrangement of our machine has been much changed and im- 
proved from that of the original one. It consists of a stout glass plate, supported 
upon a mahogany base; upon this and upon a pillar is sustained a thin revolving 
glass plate, over which, at opposite sides of the shaft, are two or four sectors of glass ; 
on one edge of these are coatings of paper with projecting points. On the opposite 
side of the revolving plate from these coatings, are sets of collecting points, which 
are connected to two pillars, bearing sliding dischargers. 

The machine is excited by bringing near to one of the sectors a piece of vulcanite 
which has been rubbed upon a cat's skin while the plate is in revolution ; a torrent of 
sparks will pass between the dischargers so long as the motion is continued. 

The power is immensely greater than that of a frictional electrical machine, exceed- 
ing in quantity that from a plate of several times the diameter. 

A descriptive pamphlet, with full directions for use, will be sent with each machine, 
and by mail, to any one who may apply for it. 



No. 
98. 



99. 



100. 



Price. 
Ritchie's Holtz Machine, with four sectors, and 20 inch revolving 

plate (see cut upon the cover), insulated pillars 115.00 

Ritchie's Holtz Machine, revolving plate- 16 inches diameter, with 

two sectors .- 60.00 

Prime Conductor, of large surface, mounted upon a glass pillar with 
separate base ; the intensity of discharge of the Holtz machine is 
much increased by its use; 12.50 and 16.00 



20 



SCHOOL APPARATUS. 




No. 101. 



No. Price. 

101. Electrical Machine. The base is a framed cross of mahogany ; the 

plate 16 inches in diameter ; the conductor is of cylindrical form, with 
hemispherical ends, handsomely japanned, and secured by screw 
mountings upon a glass pillar, with brass pedestal; the ball of the 
conductor has a hole drilled to insert the electroscope, flier, &c. ; the 
rubber plates are of brass, supported upon the pillar by brass springs ; 
the machine is substantially made 25.00 

102. Friction Cylinder ; of glass, 75 cents; of vulcanite, 1.25 

X03. Electroscope. Two pith balls suspended by a thread to a ball and rod, 

with stand; the rod is fitted to the conductor of electrical machine; 

the electroscope shows the presence of electricity on any body. . . . 1.00 

104. Gold Leaf Electroscope. A glass jar with base and cap'with brass 

stem and ball; to the stem, on the inside, are suspended two strips 
of gold foil; a slight electrical excitement causes the strips to repel 
each other. Charge the leaves by No. 102 glass rod positively ; bring 
the electroscope near any excited body; if this is positive the leaves 
diverge more ; if negative, less . . 6.00 

105. Elier. A light wheel balanced upon a point; the arms are pointed and 

curved ; place it upon the conductor, and when the machine is turned, 
the repulsion between the electricity of the points and that communi- 
cated by the points to the air, causes the wheel to revolve; in a dark 
room the points are luminous; 1.25 and 1.75 

106. Electrical Tellurian. Three balls upon centres in the connecting 

wires ; it illustrates the same principal as the flier, and shows the 
revolution of a planet and satellite, and both around the sun 2.50 

107. Dancing Image Plates. Two metallic plates, connected by silk cords ; 

a hook to suspend to conductor, and chain 3.00 

108. Dancing Images. A pair of pith figures illustrating electrical attrac- 

tion and repulsion , . . . 1.00 

100. Head of Hair. A doll's head with long hair, illustrating the repulsion 
of substances similarly charged; each hair repels every other; the 
hair of a person upon the insulating stool is affected in the same 
manner. 2.50 



ELECTRICITY. 



21 




No. 105. 



No. 116. 



No. 114. 



No. 103. No. 104. 



No. 
110. 



111. 



112. 



113. 



114. 



115. 

116. 
117. 

118. 



Price. 

Insulating Stool; 12 inches square, with cross bars and legs of solid 

glass firmly cemented in 5.50 

Note.— A board laid upon four strong glass tumblers will make a ser- 
viceable insulating stool. 

Electrical Bells. Two bells suspended upon a wire frame; one by " 
brass wire, the other by silk cord ; the latter has a chain to make con- 
nection with the earth ; an insulated ball is alternately attracted and 
repelled between the bells 3.00 

Leyden Jar. A glass jar coated outside and inside with tin foil; a cap 
of wood supports a brass stem and ball, which connects with the in- 
ner coating. To charge the jar, hold it by the foil and bring the ball 
near the conductor; to discharge, connect by the discharger the outer 
coating with the ball ; pint, 1.50; quart, 2.00; two quarts, 2.75 

Atmospheric Jar; has a hook stem to suspend it to the conductor, to 
show that ajar cannot be charged without a connection by which the 
negative electricity can flow from the earth to the outer coating; the 
jar is charged very slowly, but as electricity passes freely between 
the atmosphere and a point, by placing the ring of points upon the 
jar, it is rapidly charged ; quart, 3.00 

Movable Coating Jar, consists of a jar with closely fitting metallic 
coatings; charge the, jar as No. 112; then with a glass rod or the dis- 
charger, lift out the inner coating by its hook; the jar may now be 
safely taken from the outer vessel ; no trace of electricity will remain 
in the two coatings, and if the jar is touched on both sides, only the 
surface touched will be discharged; now replace the parts, lifting the 
inner coating as before ; the jar may now be discharged, showing that 
the electricity is accumulated on the surface of the glass, being re- 
tained by the mutual attraction of the negative and positive fluids on 
the opposite sides. The coatings serve only as conductors 3.50 

Electrometer Jar, differs from No. 112 in having a discharging rod and 
ball which may be adjusted near the outer foil ; when the jar is charged 
to a sufficient intensity (greater or less in proportion to the distance 
of the ball), the discharge takes place; quart, 2.50; two quarts, . . . 3.25 

Diamond Jar. The coatings on either side are small squares of foil; 
each perforated to show the opposite points; the discharge of the jar 
is very beautiful in a dark room; quart, 3.00 

Lightning Plate, is a large plate of glass, coated on one side with foil, 
and on the reverse with brass filings; bring the chain from the rub- 
bers of No. 101, or the earth chain of No. 100, to one edge of the fil- 
ings, and a chain from conductor to the opposite edge; the current 
will pass in beautiful zigzag lines. The plate can be charged like a 
Leyden jar; the discharge is very brilliant 2.00 

Amalgam for the rubbers of the electrical machine, in box, .25 and . . .50 



22 



SCHOOL APPARATUS. 




No. 124. 



i i . .!. ' 

No. 123. No. 122. 



No. Price 

119. Improved set of Leyden Jars; consists of a two quart electrometer 

. jar, No. 115 ; a quart atmospheric jar, No. 113, and a metallic plate ; 
remove the discharging rod and the ball from No. 115, and screw in 
its place the plate ; remove the ring from No. 113, and set it on the 
plate, and thus form a double jar ; connect the stem of upper jar with 
the [machine, and the foil of lower with the earth ; the inside of the 
upper and outside of the lower will receive positive electricity ; each 
may be discharged separately, or both together. Again connect the 
stem of lower with the machine ; this alone is charged, (unless the 
ball of upper jar is put in connection with the earth ;) then connect 
lower outer coating with ball of upper, and the lower one will be par- 
tially discharged in charging the upper one, &c $6.50 

120. Stand and Bells; A basement with pillar and bell, and a similar bell 

to screw to the stem of a Leyden jar ; a little ball suspended between 
the bells will be alternately attracted and repelled between them, vi- 
brating for a long time, and gradually discharging the jar 5.00 

121. Ether Spoon ; a metallic cup with a brass knob in the centre ; cover 

the knob with ether or warm alcohol '. a spark from conductor to 
the knob will fire the ether ; a person standing upon the insulating 
stool, may fire it by his finger or by an icicle held in the hand 1.25 

122. Spircl Spotted Tube and stand, 20 inches high ; the electric current 

passes through the tube from spot to spot in beautiful scintillations ; 
the tube may be held in the hand, or let the chain from the rubbers 
pass to the lower cap 4.00 

123. Egg Stand; for illuminating eggs ; abase with movable bars and slid- 

ing rod, for supporting eggs; the discharge of a Leyden jar beauti- 
fully illuminates the eggs, the yolk and white will be completely 
mingled 2.00 

124. Discharger ; a curved brass wire and balls upon a large glass handle. 

and a piece of chain with a hook to attach to one arm, to use when a 

longer reach is desired ; 2.00 and . 3.50 

124A. Jointed Discharger; large handle, with long curved rods, and hinged 

joint 5.25 

125. Gas Pistol, for firing a mixture of hydrogen gas and air by the electric 

spark 1.00 



ELJfcCTKlCiri 



23 




No. 128. 



No. 129. 



No. 132. 



No. 130. 



1.50 



5.00 



No. Price. 

126. Powder Borab; illustrating the effect of passing- the electric current 

through water ; pour a thimble full of powder into the bomb, place a 
charged jar upon- the chain of the bomb, thoroughly wet the cord and 
attach it to one arm of the discharger, bring the other arm to the 
ball of the jar, and the powder will be fired ; if the wet string is not 
in the circuit the powder will not be fired $2.00 

127. Sportsman and Birds ; put the birds on the electrometer jar ; at the 

instant of discharge, the birds will fall 

128. Obelisk ; illustrating the lightning rod ; a pyramid of several parts, 

resting upon a pedestal ; a lightning rod passes down through a mova- 
ble block ; if this is placed so that the rod is not continuous, it is 
thrown out by the discharge of a Leyden jar, and the obelisk falls. 

129. Dancing Balls ; 1 dozen pith balls in box ; place the receiver, No. 45, 

on a metal surface ; screw the plate of No. 119 on the sliding rod, and 
connect with machine ; or hold a glass vessel so that a piece of chain 
from the conductor will fall inside, which will charge the surface of 
the glass ; then throw in the balls 

130. Gassiot's Cascade ; a glass vase, coated on the inside with tin foil ; 

place it under the receiver, and pass the sliding rod through a piece 
of glass tube down to the foil ; let the rubber chain pass to the pump 
plate. The electrical discharge is very beautiful 

131. Aurora Tube, (see No. 63 ;) exhaust the tube and pass the electrical 

current through it; a beautiful auroral light will fill the tube; then 
place the ball of the tube at different striking distances from the con- 
ductor ; the electricity will flow in slender streams, braiding on the 
inner surface of the glass ; the effect will be changed by gradually 
admitting the air to the tube 

132. Luminous Points ; two sets of points, to screw into the pump and to 

the sliding rod ; exhaust the bell, and connect the sliding rod to the 
electrical machine ; the discharge between the points, and the flu- 
orescence surrounding- the wires, are verv beautiful <> 3.03 



.25 



2.50 



8.0G 



24 



SCHOOL APPARATUS, 



MAGNETICS. 




No. 146. 



No. 147 



No. 151. 



No. Price 

140. Bar Magnet; a flat steel permanent magnet, with poles marked N and 

S ; the lines which show the resultant action of the magnetic forces 
are shown by laying a plate of glass over the bar, and sprinkling fil- 
ings from a sieve; these lines are called magnetic curves 1.00 

141. Horse Shoe Magnet, or U magnet, with armature of soft iron; the 

glass plate and filings exhibit the magnetic curves. "When not in use 

the armature should be kept upon the poles of the magnet, 1.00 and . 1.50 

142. Magnet and "Wheel Armature: the arms of the magnet are ten 

inches in length; a cylindrical armature, with a brass wheel 3.75 

143. Magnetic Needle, with brass stand and point; the needle has a bell- 

metal centre, and is balanced to be acted upon by the earth's magnet- 
ism, as also by the attraction and repulsion of another magnet, show- 
ing that poles of opposite names attract, while those of same name 
repel each other 1 .50 

144. Dipping Needle, on stand 2.50 

145. Voltaic Pair. A plate of copper and one of zinc, connected by a cop- 

per wire and glass jar. In use, the zinc must be amalgamated with 
mercury; use ten volumes of water to one of sulphuric acid 1.50 

146. Smee's Battery. A glass jar with two thick plates of zinc, between 

which is a sheet of platinized metal. Pole cups are connected to each. 
Fill the jar with water, with one tenth its volume of sulphuric acid; 
the zinc must be kept well amalgamated with mercury *«5° 

147. Bunsen's Battery, is composed of an outer jar nine by seven inches 

diameter, a zinc cylinder nine inches by five in diameter ; a porous 
cell of unglaced earthen ware, within which is a bar of graphite. 
Strong copper ribbons are attached to the zinc and carbon by screw 
clamps. The porous cell is to be filled with nitric acid, the outer cell 
with a mixture of ten parts by volume of water, to one of sulphuric 
acid. The zinc must be kept well amalgamated 4.50 



MAG N K T I C S . 



'2b 




>"o. 152. 



Xo. 1G2. 



No. Price. 

148. Thermo Plates. German silver and bismuth, for development of elec- 

tricity by heat; single pair, 75 

149. Thermo Pile. A series of pairs of plates connect the wires to the pole 

cups of No. 15S. Heat one end of the pile moderately, keeping the 
opposite end cool : the electricity excited at the soldered junctions of 
the two metals will cause a deflection of the needle of the galvanom- 
eter; 3.00 and 5.00 

150. Powder Cup. Brass cup, with insulated wires connected by a piece of 

fine platinum wire; 1.00 and 1.75 

151. Contracting Helix. Base and pillar, with adjusting screw, a spiral of 

copper wire, and glass mercury cup; connect the pole cups to the 
battery : the current through the helix will cause the spires to attract 
each other, lifting the point out of the mercury with a spark; the 
current is thus broken, the attraction ceases, and the point again dips 
into the mercury: the wire thus vibrates rapidly; if the battery cur- 
rent passes also through the coil or helix of a large electro magnet, 
Xo. 153 or Xo. 155, the brilliancy of the spark will be much in- 
creased 5.50 

152. Decomposing Cell. A glass cup, with tubes and pole cups, from which 

platinum wires extend into the tubes ; pour acidulated water into the 
cup; fill and invert The tubes; the action of the battery will decom- 
pose water, and the gases will be collected in the tubes. The one 
connected to the positive pole of the battery (the carbon) being filled 
with oxygen, and the other with hydrogen: 3.25 and 5.25 

153. Electro-Magnet. A bent bar of soft iron, with two helices of insu- 

lated copper wire; the iron becomes a powerful magnet when in the 
circuit of a battery, but ceases to be so the instant that the battery 
connection is broken : 2.00 and 3.00 

154. Heliacal Ring. Two semi-circular pieces of soft iron, with ring han- 

dles, and a helix of copper wire ; connect the helix with the battery. 

and great force will be required to separate the ring 4.25 

155. Lifting Coil. A large and thick helix and an iron rod: connect the 

wire to the battery, and bring the end of the iron rod below the coil, 

and it will be drawn in and held in suspension. 3,00 and 5.00 

156. Revolving Magnet is a steel, permanent magnet, between the poles 

of which is a straight electro-magnet on a spindle: the current is re- 
ceived through pole cups, and passes to the electro-maamet through 
a pole changer on the spindle, arranged so that at each revolution 
each end of the electro- magnet becomes alternately a north and south 
pole, and is therefore alternately attracted and repelled by the per- 
manent magnet, producing a revolution of astonishing" rapiditv. . . . 8.00 

4 



26 



SCHOOL APPARATUS. 




No. 163. 





No. 157. 




■Hlllllllllllllllillllllllll lllllllllllllllllllllll Mini,!; ,!|.;i!lii!!: 

No. 156. No. 160. 

157- Galvanometer (Oersted's). A base and pillar supporting a wire frame, 
within which is placed a magnetic needle. The wire has three pole 
cups arranged so that the battery current may pass above, below, or 
around the needle, showing the influence of the current upon the nee- 
dle, and measuring the force of the voltaic current by the amount of 
deflection of the needle; the frame must be placed north and south. . 4.75 

158. Galvanometer, compass form; a flat helix surrounds the needle, by 

which the current passes many times around it, increasing the power 

of deflection 4.50 

159. Telegraph Model. Upon a base is placed an electro-magnet, with its 

armature attached to a spring; a point upon the spring marks the pa- 
per as it is drawn out from the reel; a signal key upon a separate 
base, with pole cups, and a long wire to extend around the room. 
Connect one pole of the battery to the model, a wire from the model 
to the signal key, and a wire from it to the other pole of the battery. 
When the signal key is pressed down, the armature instantly is drawn 
down, marking the paper . . 9.00 

160. Telegraph Model, with the signal key on the same base 8.00 

161. Model of Relay Magnet. A base and an electro-magnet of fine wire, 

over which is a movable lever, adjustable by a spring for making 
and breaking a battery circuit. Use No. 146 for the relay electro-mag- 
net, and No. 145 for telegraph model. These models will show plain- 
ly the whole operation of the Electric Telegraph 7.50 

162. Separable Helices for induction. The primary helix is supported up- 

on a base, with a vibrating and a rasp electrotome ; the core is of iron 
wires. The secondary helix is a separate bobbin, with pole cups. 
The power of the induced current is in proportion to the number of 
iron wires used. 18.00 

163. Double Helices, or shocker; similar in construction to No. 162, with 

vibrating electrotome. The core is a bundle of iron wires, which can 

be drawn out, regulating the intensity of the shock; 8.50 and . . . . 7.50 

164. Handles, with insulated wires for shocker ..*„..„ 2.00 



ELECTRICITY. 27 




No. 165. 



RITCHIE'S IMPROVED INDUCTION COIL. 

One of the most important instruments which have been brought out for many 
years, is the Induction Coil, by which all the effects of static electricity are produced 
from the battery. Its power is immensely greater than the electrical machine; the 
discharges may be made so rapidly as to appear a continuous flow, and with quantity 
so great that a Leyden jar can be charged and discharged as rapidly as the ear can 
distinguish sounds. It is not affected by the state of the atmosphere, and occupies a 
small space; the battery used is Bunsen's, of intensity of only two to four cells. 

Previous to the invention by Ritchie of his mode of winding and insulating the 
helices, the longest sparks obtained in Paris were less than an inch. By his improve- 
ment, not only was the instrument rendered capable of throwing sparks of fifteen 
inches or more, but the quantity, or volume, is greatly increased. The mode by which 
this was effected was published in Silliman's Journal, and copied into the Philosoph- 
ical Magazine, of London, and other scientific journals of Europe. 



No. Price. 

165. Induction Coil, mounted upon a mahogany base; the helix is covered 

with silk velvet, and rests upon a mahogany pedestal, and is finely 
finished. Capable of throwing the spark 6 inches 337.50 

166. Induction Coil, mounted similar to No. 165, capable of giving sparks 

of 4 inches in length 225.00 

167- Induction Coil, enclosed in a mahogany case of cubical form, mounted 
upon a base ; the break-piece and pole cups for battery current, are 
placed on the base, the dischargers upon the top, the helices, and 
other portions of the instrument cannot be shown. Capable of throw- 
ing the spark four inches 200.00 

168. Induction Coil, similar to No. 167, three inch spark 150.00 

169. Induction Coil, similar to No. 167, two inch spark 100.00 

170. Induction Coil, similar to No. 167, one inch spark 60.00 

171. Geissler's Tubes. Hermetically sealed glass tubes of different forms, 

for the electric discharge of the Holtz Machine or Induction Coil. It 
would be difficult to give a description of the beauty and brilliancy 
of the effects produced ; 2.00 to = . „ 5.00 



28 



SCHOOL APPARATUS. 



ACOUSTICS. 




■vH 



RITCHIE'S IMPROVED SONOMETER. 

The case is of mahogany, 40 inches in length, with sounding-hoard of spruce, fitted 
for two wires, with tension-keys and wrench, and a brass lever with two weights (1 to 
4), for measuring the tension (the upper line of figures is for the smaller, and the 
lower line for the greater weight). Two scales divided to the diatonic scale, with 
letters and syllables for the intervals of tones and semitones, and the ratio of length 
of cord, and number of vibrations ; and a scale of sixty equal parts, with the numbers 
for division into two, three, four, eight, &c, with movable bridges for one or both 
wires to rest upon. 

To produce the notes of the scale, move the bridge to the letters on the scale, 
and sound with the bow. 

For the experiment to show the law that the rapidity of vibration is as the square 
root of the tension, attach one wire to the lever, place the weight on some number 
and tighten the wire until the lever is brought to a level, and tune the other wire to 
unison ; then change the weight to a number on the lever corresponding to a chord ; 
thus, from 2 to 8 will be an octave; 1 to 1(5, two octaves ; 4 to 9, a fifth. 

For the experiment to show that the rapidity of vibration is inversely as the square 
root of its density, place the large wire, which is four times as heavy, on the lever, 
and the weight to 16; tune the other wire to unison, then change the large wire for 
one of same size as the second one, and raise the weight as before; it will sound an 
octave higher; change weight to 4 and it will give the unison. 

In changing considerably the weight, it will be necessary to tighten or loosen the 
screw to allow for the stretching of the wire. 

For producing overtones, or harmonics, touch with a feather, or lightly with the 
finger, the wire at one of the equal divisions, and draw the bow gently across it; the 
wire will vibrate between the feather and fixed bridge, and also in equal divisions on 
the other side of the feather, but having points of rest, or nodes, at the divisions : 
e. g., touch the feather at 20, another node will be at 40; or touch at 12, other nodes 
will appear at 24, 30, and 48, dividing the wire into three or five equal portions, vibrat- 
ing at equal times, and sounding the tone of the second and fourth harmonic of the 
fundamental note. A box of paper riders, blue and red, arc sent to place on the wire 
before sounding; put some on the nodes, which will remain still, and some of another 
color on intermediate places, which will be instantly thrown off. 

For showing sympathetic vibrations, tune one wire to unison or octave to the organ 
pipe ; or sound the note with the voice, and the wire will be thrown into vibration 
and distinctly heard; it is essential that the unison or chord be perfect, or the wire 
will not respond. Draw the piston of the pipe while sounding it; the wire will 
catch and respond to the note which was for the instant of same number of vibrations. 

By tuning the wires to near an unison, the effects of interference, or beats, are pro- 
duced. 

No. Price. 

180. Sonometer, with a set of wires, wrench, lever and weights . 25.00 

181. Sonometer, with wires and wrench the same as above, wit'iout the 

lever and weights. 20.00 



ACOUSTICS, 



29 




No. 182. No. 183. No. 187. 

No Price. 

182. Eevolving Toothed Wheel. A heavy brass wheel supported in an 

iron frame and pedestal; revolve it by a cord wound around the axis, 
and hold a card against the teeth; a shrill musical tone will be pro- 
duced, gradually falling in pitch as the speed is lessened 7.50 

183. Iron Screw Press, for confining plates and rods for vibration, with 

table clamp screw 7 # 50 

184. Brass Plate for vibration ; hold it by the middle or other point, in the 

Screw Press ; draw the bow across the edge, and from a sand box 
held high above, scatter equally over the plate a small quantity of fine 
black writing sand, which will at once collect into fine lines, showing 
the nodes, and forming beautiful figures and curves ; these are most 
readily obtained by touching the plate at one or two points with the 
finger while exciting it by the bow. 3.50 

185. Two Rods of brass for longitudinal vibration, with stand and ivory ball 

and clamps for holding them in No. 183. Vibrate by rubbing the rod 
lengthwise with a piece of resined leather; place the stand so that the 
ball touches the end of the rod ; it will be violently repelled 3.75 

186. Longitudinal Vibration of Rods ; four wooden rods fixed at one end 

in a bar, to be held by No. 183. They are tuned to 1st, 3d, 5th, and 8th. 3.50 

187. Diapason, or tuning fork on sounding case. The fork and case are both 

tuned to the same note, C 3 =512 vibrations per second; excite the fork 
with the bow. It can be removed from the case for experiments with 
the organ pipe or tubes ; the reinforcement of sound by bringing it 
over the open end of the case, or Resonant Jar, is very marked. . . . 11.00 

188. Violoncello Bow, for vibrating plates, &c 2.00 

189. Glass Tubes of 6, 3, and \% inches in length, for producing a vibration 

by blowing across the open ends 75 

190. Resonant Jar, 18 inches deep, to be partly filled with water, to be used 

with the tuning fork 2.00 

191. Organ Pipe, with movable sliding piston, giving two octaves, and also 

showing the effect of an open and a closed pipe. The notes of the di- 
atonic scale are marked on the piston 4.50 

192. Organ Reed Pipe. A beating reed enclosed in a glass chamber, 

with a sliding rest, varying the vibrating length of reeel 4.75 

193. Trevelyan's Apparatus. A brass rocker with rod and ball and block 

of lead; heat the rocker and lay it upon the block; set it in motion 

and it will vibrate so rapidly as to produce a clear musical tone. . . . 5.00 

194. Bell in Vacuum, with supporting frame and stand. The bell is sus- 

tained upon the frame by silk cords, to prevent the transmission of the 
vibration through the support. In use, screw the frame into the 
pump-plate, and ring by the Sliding-rod 3.25 

195. Ealeidophone ; a silvered ball supported upon a slender steel wire upon 

a heavy iron base, showing the superposition of vibrations. Pluck the 
ball and give it a wide vibration ; then strike the wire near the base, 
to right or left, a quick, light blow, thus giving it a vibration in anoth- 
er direction. By varying the blows, the reflected sunlight from the 
ball will give most beautiful curves and figures 2.50 

196. Jet for singing flame to attach to Hydrogen Generator. . . 1.00 



30 



SCHOOL APPARATUS 



UNDULATIONS 




Prof. Lyman's "Wave Apparatus, — exhibiting- not only the surface contour, 
but also the motions taking place in the whole mass of a liquid. 

In front of a plane surface are two series of revolving cranks, the length of the 
lower ones being half that of the upper. Two elastic wires connect the crank- pins of 
each series ; upright wires also connect each pair of cranks, and pass down through 
a plate into the base. The cranks all revolve synchronously; they thus keep their 
relative.position, and come to any particular position successively, each in its turn. 

The circles represent the orbits of as many liquid particles. The transverse wires 
represent continuous lines of particles, which at rest would be horizontal, and thus 
coincide with the lines drawn on the background, the upper being the surface line, 
the lower a line of particles one ninth of a wave's length below. The upright wires 
represent lines of particles which at rest would be vertical. Every point in these 
moving lines describes its own distinct orbit. The spaces between the wires show 
the varying distortions of sections of water originally rectangular. 

The circumference of the larger circle equals a wave's length; its radius, the height 
of a revolving pendulum keeping time with the wave. If this circle be rolled under 
a horizontal line, a point half the wave's height distant from its centre will trace the 
wave profile ; the rolling circle for all profiles down to still water is the same. The 
sharper curvature of the crests than of the troughs, and its cause, are both made ob- 
vious The wire pendulum represents the resultant of the weight and centrifugal 
force of a particle, and is normal to the wave surface. 

Since the motions are the same essentially as in nature, the various geometrical 
and dynamical points of the theory of waves are strikingly exhibited. A full descrip- 
tion, with statement of the facts and principles illustrated, will be sent with each 
instrument. It can also be had on application. 



NUMBER PRTCE 

197. Lyman's "Wave Apparatus Frame, 2C> inches long, with nine pairs of 

cranks, 35.00 



optics. 32 



OPTICS, 






No. 212. No. 202. No. 213. 

No. Price. 

201. Prism, finely polished; three inch, 1.00; four inch 1.50; five iuch, . . . 2.00 

202. Mounted Prism, suspended by points in frame, with movable joint and 

stand, so that it may be adjusted to a beam of light 6.00 

203. Achromatic Prism. A pair of flint and crown glass 7.50 

204. Prismatic Lens, or multiplying glass, mounted in tube; the lens is 

ground with a great number of plane faces 75 

205. Neutralizing Lenses. Pair of double convex and concave lenses. . . 3.00 

206. Neutralizing Lenses. Set of four double and plano-convex and con- 

cave lenses 6.00 

207. Condensing Lens, mounted on elevating stand 10.00 

208. Convex and Concave Mirrors. Ground and polished silvered 

lenses, in frame ; four inch, 4.50; six inch, 5.50 

209. Cylindrical Mirrors, similar to No. 208; four inch, 3.00; six inch, . . 4.00 

210. Multiplying Mirrors. Four inch, 3.00; six inch, 4.00 

211. Mounted Mirror, on stand, to use with a beam of light through a 

shutter, &c 4.25 

212. Model of the Eye, dissected, showing the coats, retina, iris, crystal- 

line lens, &c, with stand 8.00 

213. Illustration of long, short, and perfect sight, the projection and inver- 

sion of the image on the retina, and march of the rays through the 
crystalline lens 7.00 

214. Revolving Disk Apparatus. Mahogany base, metal frame, with 

pulleys and crank ; a shaft, with screws for confining disks 9.00 

215. Set of Disks. Circles of cardboard and paper of brilliant colors, includ- 

ing Newton's Disk and forms to show the gradual blending of one 
color into another. One set of paper is cut in such manner that they 
can be arranged so that any combination of the colors can be made in 
the circle « 1.75 

216. Newton's Disk. A card to revolve by the twisting of a double cord 

between the hands 75 

217. Newton's Rings Apparatus. A lens and plate of glass mounted in 

brass cell with screws 6.50 

218. Zoetrope. A revolving cylinder with a series of open slits, to produce 

the effect of motion by successive pictures seen through the slits. . . 5.00 

219. Stereoscope, Dr. Holmes' form; the eyes are shaded, but the picture is 

placed on a sliding bar in open light; 2.00 and 3.00 

220. Photographic Pictures. Buildings, landscapes, figures, statues, &c, » 

plain and colored ; from .15 to 50 

221. Compound Microscope, with adjustable draw tube, double system of 

objectives, in mahogany box. „.„<... 4.50 

222. Compound Microscope, adjustable tube, with condensing lens, and 

triple system of objectives, in mahogany box 8.00 



32 



SCHOOL AFPAKATUS. 




No. 223. 



No. Price. 

223. Magic Lantern, of improved construction, made of heavy tin, hand- 

somely japanned ; the condensers are of superior quality, four inches 
in diameter, mounted in brass cell; the magnifiers are a combination 
of meniscus and piano lenses, a late improvement, by which the 
spherical aberration is well corrected, and all parts of the picture 
brought into focus, and distinctly thrown upon the screen; these are 
mounted in a brass tube with a diaphragm; an improved solar or 
petroleum lamp, with silver-plated reflector, and spring holder for 
sliders 40.00 

224. Ritchie's Improved Porte Lumiere, for reflecting the rays of the 

sun through the shutter of a darkened room ; a mirror of 13 by 4 
inches is supported upon a brass revolving plate in such a manner 
that it can be placed in any position, and have the motions easily 
given to reflect the solar rays horizontally through the opening. It 
is attached to a brass frame and plate, to be screwed upon the out- 
side of the shutter. On the inner side is a tube for the lenses, with 
diaphragms of different apertures; it can be used in a window of 
East, South, or West aspect; the importance and advantages of hav- 
ing a room thus fitted can hardly be over-estimated for experiments 
and illustrations, both in heat and in light 35.00 

225. Attachment for Pictures, including condensing lens mounted in cell, 

magnifying lenses mounted in tube similar to those in No. 223, with 
supports and adjustments for lenses, and for pictures. 
The effects produced by solar light are far superior to those with arti- 
ficial light 27.50 

226. Achromatic Magnifying Lenses, for No. 223, or No. 224, additional 

price, . 10.00 



We keep a selection of sliders, American and foreign views, &c, made by W. Lang- 
enheim, of Philadelphia, and others, but cannot give space to transfer their cata- 
logues to our pages. We confine our assortment of pictures principally to scientific 
cubjects, of a quality we think unequalled; a condensed list is given on next page. 



OPTICS. 



33 



The following is a catalogue of pictures which are made especially for us by Dr. 
D. H. Briggs ; the subjects are selected from the best authorities, photographed, and 
colored in the highest style of the art. 



NUMBER PRICE 

237- Astronomy, set of thirty pictures, in 3 inch single sliders, in box, includ- 
ing diagrams and telescopic views by Naysmith, Lord Rosse, De la 

Rue, and Lockyer, viz. : 45.00 

Systems of Ptolemy and Tycho Brahe. Copernician system. Spot on 
the sun, as seen by a powerful telescope (Naysmith). Phases and ap- 
parent dimensions of Venus. Inclinations of the axes of the planets. 
Diagram illustrating refraction. Parallels, meridians, and zones. 
True and mean place of a planet in its orbit. Seasons, length of days, 
etc. Signs of the zodiac. Telescopic views of the moon. Cause of 
the moon's phases. Mountains on the moon (Naysmith and De la 
Rue). Inclination of the moon's orbit. Diagram to explain eclipses. 
Total eclipse of the sun (De la Rue). Illustration of the tides. Tel- 
escopic views of Mars (Lockyer), of Jupiter (De la Rue), and of Sat- 
urn. Comet of 1811. Comparative size of the sun and planets. North 
circumpolar stars. Orion and adjacent constellations. Star cluster, 
or resolvable nebulae. Dumb-bell nebulae in Leo (Lord Rosse). Lord 
Rosse's telescope. 

238. Astronomy ; set of twenty 3 inch pictures from the above, .... 30.00 

239. Anatomy and Physiology; set of twenty 3 inch pictures, .... 30.00 

Human Skeleton. Skull. Section of the spine, etc. Teeth, and struc- 
ture of the same. Muscles, front view. Muscles, back view. Mus- 
cles of the head, neck, and face. General view of digestive organs in 
place. The digestive organs. The stomach, liver, and pancreas. 
Thoracic duct. Heart and lungs. Diagram of circulation. Skin. 
Brain and spinal cord. General view of the nerves. Fifth pair of 
nerves. Facial nerves. Diagram of the eye. Anatomy of the ear. 30.00 

240. Geology; set of twenty 3 inch pictures, including geological record, ideal 

section of the earth's crust, thickness of the earth's crust, section of 
volcano in action, Fingal's cave, grotto of Antiparos, glacier of Mount 
Rose, glacier tables, corals and coral islands, trilobites, ammonites, 
rain drop marks, pterichthys, coccostes, cephalaspis, fossil fern, a 
thrust in a coal mine, ichthyosaurus, plesiosaurus, pterodactyle, fos- 
sil foot marks, the mammoth restored, 30.00 

241. Botany; set of twenty 3 inch pictures, 30.00 

242. Natural History ; illustrations of various classes of mammalia, birds, rep- 

tiles, fishes, insects, Crustacea, annelida, mollusca, and radiata, each . 2.75 

243. Historical Subjects ; copies of celebrated pictures ; manners and cus- 

toms of the East ; animals and plants mentioned in the Scriptures, each 2.75 

244. Numerous illustrations of Bible lands, including views in Palestine, 

Egypt, Assyria, Petraea, &c. Floral subjects in variety. Prices of 

the above in 3 inch sliders, each 2.75 

245. Statuary, many of the most noted of antique and modern art, three inches 

diameter, with black background, 1.50; with blue, crimson, or gold 
background, each 2.00 

246. Newton's Disc; revolving slider with prismatic colors for recomposing 

white light, 7.50 

247. Chromatropes ; a variety of beautiful chromatropes, unsurpassed in bril- 

liancy and colors, 5.00 

5 



34 



SCHOOL APPARATUS, 



CHEMISTRY. 





No. 241. 



No. 242. 



No Price. 

241. Gasometers. A pair, of copper, with side tubes enclosing balance 
weights, mounted on base with casters ; brass tubes, with stop-cocks; 
cylindrical pressure weights; the bells 7}£ inches diameter by 17 
inches in height 70.00 

242: Gasometer. Cylindrical bell and cistern, made of thick, galvanized, 
japanned metal, and painted with a preparation nearly insoluble. A 
movable metal crane, with pulleys and balance weight made in sec- 
tions ; by removing one or more a corresponding pressure is exerted 
on the gas ; the bell is 16 inches in diameter, and 26 inches high. Ca- 
pacity 22 gallons, and is warranted to be strong and durable. .... 35.00 

243. Gasometer. Similar to No. 242; the bell is 11 inches diameter, and 24 

inches high 30.00 

244. Pneumatic Trough, of stout, galvanized iron; 20 inches long by 15 

wide, and 12 inches deep, with movable shelf; japanned 7.50 

245. Gas Bag, of square form, of vulcanized rubber-cloth, with socket, 18 by 

20 inches; capacity, 15 gallons 8.25 

246. Gas Bag, with socket, 24 by 30 inches; capacity, 35 gallons 12.00 

247. Gas Bag, with socket, 30 by 40 inches; capacity, 55 gallons ; . 15.00 

248. Gas Bags of rubber, oval, 1 to 4 gals., with sockets, 2.50 to 5.25 

249. Hydrogen Generator of glass, with inverted bell and stop-cock, a 

copper basket for granulated zinc, and a solid ball of zinc; the cover 

is held by screws beneath a flange 9.00 



CHEMISTRY 



35 






No. 315. 



No. 275. 



No. 249. 



No. Price, 

250. Gas Generator of glass, with inverted bell, basket for zinc; the bell is 

attached to a rubber tube, with nipper tap 5.00 

251. Oxygen Flask of copper, thick bottom, screw cap ; one quart, .... 5.50 

252. Oxygen Flask, similar to above with gallows screw cap 8.00 

253. Bottle Generator, pint, with rubber cork and tubes 1.00 

254. Nitric Oxide Bell and Jar ; the jar is ten inches by four in diameter, 

the bell one half its capacity; both ground to fit a glass plate. . . . 2.50 

255. Oxy Hydrogen Concentric Jet with adjustable lime-holder, and 

gallows screw connections 18.00 

256. Rubber Hose to connect oxy-hydrogen jet to Gasometers or bags, each 

six feet long, with brass sockets 6.00 

257. Platinum Sponge, jet and holder to attach to No. 249 1.75 

258. Bottles and Tube for illustrating the diffusion of gases; two bottles 

with rubber corks, connected by a glass tube 1.00 

259. Mercury- The price is variable; our charge will depend on its commer- 

cial value. At present it is, per pound, 1.00 

260. U Tube, with one end closed, tubulated near the bend, to which is at- 

tached a piece of rubber tube with a nipper tap 2.50 

261. Glass Cylinder, with foot, 7 by \% inches, ground mouth and plate. . 1.50 

262. Glass Cylinder, with foot, 5 by 1 inch diameter, and plate 1.00 

263. Flat Glass Dish, 9 inches diameter, 2 inches deep 1.50 

264. Cylindrical Jar, with ground edge ; two quarts. . . *. 1.50 

265. Endosmeter, or osmose apparatus; a glass bell over which to tie a 

membrane, with glass tube and rubber cork 1.75 

266. Porous Cup and Tube, for osmose of gases 1.00 

267. Chlorine Tube, of glass, fifteen inches long, closed at one end; an in- 

terior jet tube with rubber to connect to a funnel 1.50 

268. Eudometer, a D tube closed at one end, with platinum electrodes for 

exploding gases ; plain, 3.00; graduated, 4.00 

269. Rubber Corks, assorted to one inch diameter, one dozen in box 35 

270. Bunsen's Burner, with stand 1.50 

271. Evaporating Dishes, porcelain, 33, 40, 50, and 60 

272. Chalk Cup, 2 inches by 1% diameter 50 

273. Nipper Tap, or spring stopcock for closing tubes; 35 cents and 50 

274. "Wash Bottle, with tubes and rubber stopper 1.75 

275= Lamp Stand, with three bows and binding screws, 2.00; four bows, . 2.25 

276. Iron Chimney for lamp 35 

277. Rubber Tubing, of calibre from eighth to half inch ; per foot, 12 to . .35 

278. Cork Borers: set of three, 2 25 : set of six, 3.25 

279. Hydrogen Balloons, of goldbeater's skin, 3.00 to 6.00 

280. Pendent Spoon and Rod. copper, 50 cents ; platinum, 1.50 

281. Retort Holder, base and pillar, with two pair of spring and screw jaws 

for holding tubes, retorts, &c 3.50 



36 SCHOOL APPARATUS. 

No. Price. 

282. Evaporating Dishes, porcelain, nests of six „ . . 2.00 

283. Hessian Crucibles, in nest, „ . „25 

284. Porcelain Mortar and Pestle; 1.00 to 3.00 

285. Agate Mortar and Pestle ; 1.50 to 7.00 

286. Sheet Rubber, piece, for square foot, 50 

287. Dissolved Rubber, in tin boxes, 75 

288. Crucible Tongs, of iron ; 1.00 and 2.50 

289. Sefstroem's Retort Solder, wood clamps, mounted on iron stand. . . 5.00 

290. Nipper Tube Holder, wood screw clamps with cork jaws 3.00 

291. Copper Alcohol Lamp, with five wicks 2.25 

292. Spirit Lamp, with ground cap 1.00 

293. Plain Mouth Blowpipe, of brass 50 

294. Blowpipe, with condensing bulb 1.50 

295. Test Tubes, with mahogany stands ; 12 tubes, 2.00 and 3.25 

296. Mouthpiece for inhaling gas 2.00 

297. Filtering Paper, in packages ; 75 cents to 1.00 



Chemical Glass Ware. 

298. Receivers of different forms, see Pneumatics. 

299. Hydrometer Jar, with foot and lip 1.25 

300. Bolt Heads, or Matrass, pint, fifty cents ; quart 75 

301. Funnels, gill, 25 cents ; half pint, 35 cents ; pint, 45 cents ; quart, .... .60 

302. Graduated Ounce Measure; 2 oz. 65 cents; 4 oz. 75 cents; 8oz. . . . 1.00 

303. Stirring Rods, set of six, 50 

304. Safety Tubes ; straight, 25 ; bent with bulbs, 60 

305. Pipette, or Dropping Tube; 25 and 50 

306. Two Bulbs and Tube, Brand's, for condensation, 75 

307. Glass Chemical Tubes; per pound, 75 cents to 1.25 

308. Glass Barometer Tubes, small and large, per pound, 1.50 

309. Rupert's Drops, unannealed glass, per dozen, 1.00 

310. Bologna Vials, unannealed ; per dozen, 2.25 



Bohemian Hard Glass without Lead. 

311. Retorts ; half pint, 40 cents ; pint, 55 cents ; quart, 65 

312. Retorts; tubulated, 3 oz., 40 cents; 4 oz., 50 cents; half pint, 60 cents; 

pint, 76 cents; quart, 1.00 

313. Flasks, with rim necks for corks, uniformly thin throughout; 4 ounce, 

30 cents; ha4f pint, 35 cents; pint, 50 cents; quart, 65 

314. Digesting Flasks, with flat bottoms and rim neck ; 2 oz., 30 cents ; 4 oz. 

30 cents ; half pint, 35 cents ; pint, 50 cents ; quart, 65 

315. Woulfe's Bottles, with three necks ; pints, 1.25; quarts, ...<,... 1.50 

316. Globe Receivers, tubulated ; half pint, 50 cent; pint, 65 cents; quart,. .75 

317. Beaker Glasses, in nest; 1.25 to 3.50 

318. Test Tubes, with rim and lip ; per dozen, 50 cents to . 1.25 



ASTRONOMY, &c. 37 

Globes. — Terrestrial and celestial globes, made by G. Joslin, of Boston (late Lor- 
ing). These globes are considered the most accurate of any now made ; the engrav- 
ings have been corrected to late discoveries and geographical changes, and are of 
superior construction. 



No. Price. 

320. Globes on bronzed pedestal stand, with casters; this style of mounting 

has the advantage of great stability, convenience, and beauty of de- 
sign ; 12 inch, 37.50 ; per pair, 75.00 

321. Globes, 12 inch, on full frame stand, each 22.00; per pair, 44.00 

322. Globes, 10 inch diameter, frame stand, each 17.00; per pair, 34.00 

323. Globes, 10 inch, semi-stand, each 10.00; per pair, 20.00 

324. Globes, 6 inch, semi-stand, each 5.00; per pair, 10.00 

325. Joslin's Solar Telluric Globe 15.00 

320. Improved Seasons Machine, giving the motions of the earth around 

the sun, the inclination and parallelism of the earth's axis, the causes 
of the seasons, the revolution of the moon around the earth, the 
moon's nodes, the revolution of the sun and earth on their axes; five 
inch sun, three inch terrestrial globe for the earth 14.00 

327. WhitaPs Movable Planisphere of the Heavens, with the Con- 

stellations handsomely colored. 
The starry heavens arc delineated on a movable planisphere, exhibiting 
the position of the constellations in the firmament, as seen in the 
United States every five minutes during the year. The right ascen- 
sion and declination of the sun, moon, stars, and planets; equation 
of time (sun fast or slow); harvest moon; sun and moon running 
high or low; the milky way, as it changes its course every hour; 
change of seasons; variation of the magnetic needle, &c, can be 
readily explained by this valuable substitute for a celestial globe, 
with fuil explanations for the use of the planisphere, and of the 
problems which may be solved. Plain, £.50; colored, 3.00 

328. Rain Gauge, of improved form ; copper cylinder with exterior glass 

tube and graduated scale 14.00 

329. Geometrical Solids. Set of thirteen, including three and six-sided 

prisms, cylinders, cone, pyramid, frustums of cone and pyramid, 
sphere, hemisphere, oblate and prolate spheroids, neatly made in fine 
wood, and in box 2.00 

330. Models of Crystals. Thirteen pieces, giving the fundamental forms, 

according to Dana, in large size 3.25 

331. Cube Root Solids, illustrating the extraction of square and cube roots, 

of mahogany, in box 1.25 

332. Set of 64 inch Cubes, for same illustrations in box 1.75 

333. Set of Solids, illustrating the mensuration of solids; ten cubes, rec- 

tangular and oblique prisms, papered, with lines 1.50 

334. Dissected Cone, illustrating conic sections; viz., the circle, ellipse, 

parabola and hyperbola, made in an improved manner, so that the di- 
visions fit accurately, and outline of cone is unbroken; the parts are 
connected by dowels 3.00 

335. Plotting Instruments, including a compass with shifting leg, ink and 

crayon points, a pair of dividers, and line pen, in box . 4.50 



SELECTIONS 



SCHOOL APPARATUS, 

COMPILED FROM THE 

CATALOGUE. 



SET 

Laws of Matter. 
UTo. Price. 

5. Capillary Tubes 1.00 

8. Collision Balls 3.50 

10. Centre of Gravity 5.00 

11. Illustration of Pulleys 20.00 

12. Illustration of Levers 5.50 

18. Central Forces * 3.75 

Hydrostatics. 

20. Equilibrium Tubes 3.50 

24. Siphon 50 

27. Lifting- Pump 9.00 

34. Hydrostatic Press 9.00 

Pneumatics. 

40. Air Pump 25.00 

44. Keceiver, quart 1.00 

44. Keceiver, gallon 2.00 

47. Hand Glass 1.25 

53. Bacchus Illustration 2.75 

54. Magdeburg Hemispheres. . . . 7.50 
58. Barometer Tube 1.50 

259. Mercury 2.00 

63. Guinea and Feather Tube. . . . 8.00 

66. Cylinder and Weights 25 

69. Oil. 25 

Heat. 

70. Palm Glass 1.00 

73. Bar and Gauge 2.25 

74. Compound Bar 1.25 

75. Fire Syringe 3.00 

Electricity. 
101. Electrical Machine. ...... 25.00 

103. Electroscope. l.oo 



No. 1. 

No. Price. 

105. Flier 1.25 

111. Set of Bells 3.00 

112. Leyden Jar 2.00 

122. Spiral Tube 4.00 

124. Discharger 2.00 

118. Amalgam 25 

Magnetics. 

141. U Magnet 1.00 

143. Needle and Stand 1.50 

146. Smee's Battery 4.50 

153. Electro Magnet 2.00 

159. Telegraph Model. ....... 9.00 

163. Shocker 7.50 

164. Handles and Wires. ...... 2.00 

Optics. 

201. Prism 1.50 

205. Pair of Lenses 3.00 

208. Concave and Convex Mirrors. . 4.50 

216. Newton's Disk 75 

221. Microscope , -. 4.50 



He capitulation. 

Laws of Matter 38.75 

Hydrostatics 22.00 

Pneumatics 51.50 

Heat . 7.50 

Electricity 38.50 

Magnetics 27.50 

Optics 14.25 

$200.00 



SCHOOL APPARATU 



39 



SET No. 2. 

Arranged for and adopted by the City School Committee, for the 

BOSTON GRAMMAR SCHOOLS. 



Laws of Matter. 
No. Price. 

2. Lead Hemisphere 1.00 

3. Inertia Apparatus 1.75 

5. Capillary Tubes 1.00 

6. Capillary Plates 1.50 

8. Collision Palls 3.50 

9. Centre of Gravity 10.00 

14. Mechanical Powers 33.00 

18. Central Forces 3.75 

19b. Illustration of the Pendulum. . 3.50 

Hydrostatics. 

20. Equilibrium Tubes 3.50 

22. Upward Pressure of Liquids. . . 3.00 

25. Tantalus Cup 2.00 

27. Model of Pump. .... .... 9.00 

29. Archimedes Principle 2.50 

Pneumatics. 

40. Air Pump 25.00 

44. Receiver, one quart 1.00 

45. Sliding Rod Receiver 5.00 

47. Hand Glass 1.25 

48. Condenser 9.50 

49. Condensing Chamber 8.50 

51. Expansion Bolthead 75 

53. Bacchus Illustration 2.75 

54. Magdeburg Hemispheres 7.50 

56. Weight and Buoyancy 7.50 

59. Barometer Apparatus 6.00 

63. Guinea and Feather Tube 8.00 

64. Air Gun 1.25 

66. Cylinder and Weight 25 

68. Washers and Oil 50 



Heat. 

71. Pulse Glass 1.00 

72. Ring and Ball 2.25 

74. Compound Bar 1.25 

75. Fire Syringe 3.00 

76. Reflectors 9.00 

78. Wire Gauze 75 

82. Ventilation 3.50 

86. Conductometer 4.50 

292. Spirit Lamp 1.00 



Electricity. 
99. Holtz Machine. . . . 



100. 
102. 
103. 
105. 

110. 
114. 
117. 



Prime Conductor. 
Friction Cylinder. 
Electroscope. . . 
Flier 



60.00 

12.50 

.75 

1.00 

1.25 



Insulating Stool 5.50 

Movable Coating Jar 3.50 

Lightning Plate 2.00 



No. Price. 

120. Stand and Bells 5.00 

121. Ether Spoon 1.25 

122. Spiral Tube 4.00 

124. Discharger 2.00 

125. Gas Pistol 1.00 

126. Powder Bomb 2.00 

129. Dancing Balls. 50 



Magnetics. 

140. Bar Magnet • . . 1.00 

142. U Magnet, and Wheel 3.75 

143. Needle and Stand 1.50 

147. Bunsen's Battery 4.50 

150. Powder Cup 1.75 

153. Electro Magnet 2.00 

154. Heliacal Ring 4.25 

156. Revolving Magnet 8.00 

157. Galvanometer 4.75 

159. Telegraph Model, 9.00 

163. Double Helices 7.50 

164. Handles and Wires 2.00 

Acoustics. 

180. Sonometer 25.00 

183. Screw Press 7.50 

184. Vibrating Plate 3.50 

188. Violoncello Bow 2.00 

191. Organ Pipe 4.50 

194. Bell in Vacuum 3.25 

Optics. 
201. Prism 1.50 

204. Multiplying Lens 75 

205. Convex and Concave Lenses. . 3.00 
208. Convex and Concave Mirrors. . 4.50 

212. Model of the Eye 8.00 

216. Newton's Disk 75 



Geometry. 

329. Set of Solids 2.00 

330. Crystal Models . 3.25 

332. Cube Root Solids 1.75 



119. Improved set of Jars. 



.50 



Recapitulation. 

Mechanics 

Hydrostatics 

Pneumatics 

Heat 

Electricity 

Magnetism 

Acoustics 45.75 

Optics 18.50 

Geometry 7.00 



59.00 
20.00 

84.75 
26.25 
108.75 
50.00 



$428.00 



40 



SCHOOL APPARATUS. 



SET No. 3. 

The following Set has been prepared with the assistance of the authors, for the 
Hand Book of Natural Philosophy, of the Cambridge Course of Physics. 



No. 

73. 

313. 
2. 
283. 
309. 
264. 
305. 
318. 
259. 



Cohesion. 



Price. 



Bar and Gauge 2.25 

Two Flasks and Tubes 1.25 

Lead Hemispheres 1.00 

Crucibles 25 

Six Rupert's Drops 50 

Two quart Cylindrical Jar. . . . 1.50 

Dropping- tube 50 

Six Test-tubes 50 

Mercury 5.00 



Adhesion. 

23. Glass Disk, with Cord 1.50 

301. Two Funnels, and Filters. . . . 1.00 

5. Set of Capillary Tubes 1.00 

301. Glass Funnel Tube 25 

265. Apparatus for Osmose 1.75 

258. Bottles and Tube 1.00 

266. Cup and Tube 1.00 



Mechanics. 

10. Centre of Gravity 5.00 

20. Liquid Equilibrium Tubes. . . . 3.50 

34. Hydrostatic Press 9.00 

31. Hydrometer 1.25 

29. Cylinder and Cup 2.50 

40. Ritchie's School Air Pump . . . 25.00 

45. Sliding-rod Receiver 5.00 

44. Plain Quart Receiver. ..... 1.00 

56. Weight and Buoyancy 7.50 

54. Magdeburg Hemispheres. . . . 7.50 
47. Hand Glass 1.25 

55. Rubber Bag and Cap 2.25 

58. Barometer Tube 1.50 

27. Model of Lifting Pump 9.00 

24. Siphon 50 

25. Tantalus Cup 2.00 

63. Guinea and Feather Tubo. . . . 8.00 

19. Illustration of Pendulum. . . . 3.50 

18. Central Forces 3.75 

12. Models of Levers 5.50 

11. Models of Pulleys 20.00 



Sound. 

194. Bell for Vacuum 3.25 

182. Revolving Toothed Wheel. . . 7.50 

187. Tuning Fork and Case 11.00 

1^0. Sonometer, with Wires 25.00 

188. Violoncello Bow 2.00 

184. Vibrating Plate 3.50 

185. Brass Rods and Ivory Ball. . . 3.75 

183. Iron Screw Press 7.50 



No. Price. 

190. Resonant Jar 2.00 

191. Organ Pipe with Sliding Piston. 4.50 

Light. 

201. Prism 2.00 

214. Revolving Disk Apparatus. . . 9.00 

215. Set of Disks 1.75 

217. Newton's Rings. . 6.50 

218. Convex and Concave Mirrors. . 4.50 
206. Neutralizing Lenses 3.00 



Heat. 

Differential Thermometer. . . . 3.50 

Conductometer 4.50 

Specific Heat 175 

Pair of Plates 1.50 

Compound Bar 1.25 

Convection of Gases 3.50 

Mason's Hygrometer 4.00 

Fire Syringe and Tinder. . . . 3.00 

Spirit Lamp 1.00 



75. 

292. 



140. 
141. 
145. 
147. 
143. 
157. 
153. 
155. 
156. 
160. 
152. 
163. 
150. 
102. 
101. 
112. 
124. 
104. 
120. 



Electricity. 

Bar Magnet. 1.00 

U Magnet 1.00 

Voltaic Pair 1.50 

Bunsen's Cell 4.50 

Magnetic Needle - 1.50 

Galvanometer 4.75 

Electro-Magnet 3.00 

Lifting Coil 3.00 

Revolving Magnet 8.00 

Model of Telegraph 8.00 

Decomposing Cell 3.25 

Vibrating Shocker 7.50 

Powder Cup 1.00 

Vulcanite Cylinder 1.25 

Electrical Machine 25.00 

Leyden Jar 2.00 

Discharger 2.00 

Electric Wheel 1.25 

Stand and Bells 5.00 



Recapitulation. 

Cohesion 12-75 

Adhesion 7.50 

Mechanics 124.50 

Sound 70.00 

Light 26.75 

Heat 24.00 

Electricity 84.50 

$350.00 



SCHOOL APPARATUS. 



41 



SET No. 4. 

Additional to the Set No. 3, specially adapted to the Cambridge Course Of 

Physics. 

Cohesion. 
No. Price. 
2?1. Two Evaporating Dishes. . . . 1.00 
2G0. U Tube, with Nipper Tap. . . . 2.50 
281. Retort and Tube Holder. . . . 3.G0 
259. Mercury G.00 



Adhesion. 

263. Glass Dish 1.50 

6. Pair of Capillary Plates. . . . 1.50 

261. Cylindrical Jar 1.50 

202. Cylindrical Jar 1.00 

258. Bottles with Tubes 3.50 

48. Condenser 9.00 

49. Condensing Chamber 0.50 

13. Screw, Wedge, Inclined Plane. 7.50 

64. Air Gun 1.25 

65. Revolving Jet 2.50 

36. Barker's Mill 1.25 

77. Wollaston's Engine 5.50 

Sound. 

186. Vibrating Rods on Bar 3.50 

189. Three Glass Tubes 75 

192. Organ Reed Pipe 4.75 

196. Jet for Singing Flame 1.00 



Light. 
207. Condensing Lens, Mounted. . . 10.00 

202. Mounted Prism, dif. over 201. . 4.00 

203. Achromatic Prism 7.50 

218. Zoetrope 5.00 

211. Mounted Mirror 4.25 



No. Price 

219. Stereoscope, with 12 Diagrams. 4.50 

81. Iodine Cell „ 5.00 

90. Hygrodcik, difference over 89, . 11.00 
76. Pair of Reflectors, and Ball. , . 12.50 



Electricity. 

144. Dipping Needle 2.50 

154. Helix and Ring. 4.25 

161. Model of Relay Magnet 9.50 

149. Thermo-Electric Series 3.00 

162. Helices, dif. over 163 10.50 

99. Holtz Machine, dif. No. 20, . . . 35.00 

100. Insulated Conductor 12.50 

108. Gold Leaf Electroscope 6.00 

110. Diamond Jar 3.50 

122. Spotted Tube 4.00 

130. Gassiot's Cascade 2.50 

171. Geissler's Tubes 10.00 



Recapitulation. 
Including Set No. 3. 

Cohesion . . 25.75 

Adhesion 13.00 

Mechanics 175.00 

Sound 80.00 

Light 66.00 

Heat 52.60 

Electricity 187.75 

$600.00 



SET No. 5. 

Designed for the Hand Book of Chemistry, Cambridge Course of Physics. 



261. Cylinder and Plate 1.50 

262. Cylinders and Plate 1.00 

264. Two Jars, 2 qts., ground edge. 3.00 

273. Two Nipper Taps 70 

248. Gas Bag, two gallons 3.00 

253. Bottle Generator 1.00 

313. Three half pint Flasks 1.05 

275. Lamp Stand. . . 2.00 

292. Spirit Lamp. . . 1.00 

281. Retort Holder. ........ 3.50 

267. Chlorine Tube, , . . , . . . 1.50 



6 



317. TwoBeakers 50 

271. Two Evaporating Dishes 50 

268. Eudiometer 3.00 

272. Chalk Cup 50 

274. Wash Bottle 1.75 

254. Nitric Oxide Bell 2.50 

311. Half Pint Retort. , 40 

318. Test Tubes, one dozen. .... .50 

307. Glass Tubing, half pound. . , .50 



277. Rubber Tube, three feet. 



. .60 
$30.00 



42 



SCHOOL APPARATUS, 



SET No. 6. 



No. 
2. 
5. 



Laws of Matter. 

Price 

Lead Hemispheres 1.00 

Capillary Tubes 1.00 

6. Capillary Plates 1.50 

8. Collision Balls 3.50 

9. Centre of Gravity 10.00 

14. Mechanical Powers 33.00 

18. Central Forces 3.75 

19 A. Parallelogram of Forces. . . 7.50 
19 b. Pendulum 3.50 

330. Crystal Models 3.25 



Hydrostatics. 

20. Equilibrium Tubes 3.50 

22. Cylinder and Plate 3.00 

23. Liquid Adhesion 1.50 

24. Siphon 50 

25. Tantalus Cup 2.00 

28. Set of Pumps 22.50 

29. Archimedes Principle 2.50 

31. Hydrometer 1.25 

299. Hydrometer Jar 1.25 

34, Hydrostatic Press 9.00 

36. Barker's Mill 1.25 



Pneumatics. 

41. Air Pump 100.00 

44. Receiver 1.00 

45. Receiver 5.00 

46. Cylindrical Jar 1.50 

47. Hand Glass 1.25 

48. Condenser 9.50 

4 ( J. Condensing Chamber 8.50 

52. Freezing Apparatus 4.00 

54. Magdeburg Hemispheres. . . . 7.50 

55. Rubber Bag 2.25 

56. Weight and Buoyancy 7.50 

59. Barometer Apparatus 6.00 

259. Mercury 2.00 

00. Fountain 6.50 

03. Guinea and Feather Tube. . . . 8.00 

64. Air Gun 1.25 

05. Revolving Jet 2.25 

66. Wood Cylinder 25 

68. Washers 25 

69. Oil 25 



Heat. 

71. Pulse Glass 1.00 

73. Bar and Gauge 2.25 

74. Compound Bar. . 2.25 

75. Fire Syringe 3.00 

76. Reflectors 12.50 

77. Wollaston's Engine 5.50 



Wo. Price. 

78. Wire Gauze 75 

79. Specific Heat 1.75 

80. Plates for Radiation 1.50 

82. Principle of Ventilation 3.50 

84. Thermometer 1.25 

85. Differential Thermometer. . . . 3.50 

86. Conductometer 4.50 

87. Eolipile 3.50 

88. Pyrometer 7.50 

89. Psychrometer 4.00 

292. Spirit Lamp 1.00 

Electricity. 

99. Holtz Machine 60.00 

100. Prime Conductor 12.50 

102. Friction Cylinder 1.25 

103. Electroscope 1.00 

105. Flier 1.75 

108. Gold Leaf Electroscope. .... 6.00 

110. Insulating Stool 5.50 

114. Movable Coating Jar 3.50 

116. Diamond Jar 3.00 

117. Lightning Plate 2.00 

119. Set of Jars 6.50 

120. Stand and Bells 5.00 

121. Ether Spoon 1.25 

122. Spiral Tube 4.00 

124A. Discharger 5.25 

126. Powder Bomb 2.00 

128. Obelisk 5.00 

129. Dancing Balls, two dozen 50 

130. Gassiot's Cascade 2.50 

132. Luminous Points . 3.00 



Magnetics 

140. Bar Magnet. 1.00 

142. U Magnet and Wheel 3.75 

143. Needle and Stand 1.50 

145. Voltaic Pair 1.50 

140. Smee's Battery 4.50 

149. Thermo Pile 5.00 

150. Powder Cup 1.75 

151. Contracting Helix 5.50 

152. Decomposing Cell 5.25 

153. Electro Magnet 3.00 

154. Heliacal Ring 4.25 

155. Lifting Coil 5.00 

150. Revolving Magnet 8.00 

158. Galvanometer 4.50 

159. Telegraph Model 9.00 

161. Relay Model 7.50 

162. Separable Helices 18.00 

104. Handles and Wires . 2.00 

171. Geissler's Tubes. ....... 12.50 



SCHOOL APPARATUS. 



43 



Acoustics. 
No. Price. 

180. Sonometer 25.00 

182. Toothed Wheel 7.50 

183. Screw Press 7.50 

184. Vibrating Plate 3.50 

185. Longitudinal Vibration 3.75 

186. Vibrating Rods 3.50 

187. Diapason 11.00 

188. Violoncello Bow. . . . . *. . . 2.00 

190. Resonant Jar 2.00 

191. Organ Pipe 4.50 

192. Reed Pipe 4.75 

193. Trevelyan's Apparatus 5.00 

194. Bell in Vacuum 3.25 

195. Kaleidophone 2.50 

Optics. 

202. Mounted Prism 6.00 

203. Achromatic Prism 7.50 

206. Neutralizing Lenses 6.00 



No. Price. 

208. Convex and Concave Mirrors. . 4.50 

211. Mounted Mirror 4.25 

212. Model of Eye 8.00 

214. Revolving Disk Apparatus. . . 9.00 

215. Set of Disks 1.75 

217. Newton's Rings 6.50 



Recapitulation. 

Laws of Matter 68.00 

Hydrostatics 48.25 

Pneumatics 174.75 

Heat 59.75 

Electricity 131.50 

Magnetics. . 103.50 

Acoustics 85.75 

Optics 53.50 

$725.00 



The above sets have been compiled with the view to combine instruments for the 
illustration of as many and as varied principles as the limits of the amount of each 
will permit, to avoid duplications, and as far as possible to represent proportionately 
each department of physical science. 

"Where the requirements of the Institution would be better subserved by giving 
greater prominence to particular branches, a selection may be made by taking the 
separate departments from dhTerent sets. 

It will be seen that some valuable instruments have not been included in either.of 
the sets, but only those that are generally required; the purchaser can add such to 
his order, or make such other changes as he may desire. 

All the articles in this Catalogue are, in size and quality, such as will make them 
suitable for portions of a most extensive cabinet. Our large Catalogue contains many 
instruments, in all departments, omitted in this simply because they are beyond the 
requirements of our high schools generally. 



E. S. HITCHIS & SONS, 



Manufactory, Brookline. Office, 149 Tremont Street, fronting the Common, 
BOSTON, MASS. 



Testimonials. 



Boston, Aug. 10, 1857. 
I take pleasure in bearing testimony to the great skill, faithfulness, and ingenuity 
of Mr. Ritchie, as a maker of Philosophical Instruments. Uniting an ample knowl- 
edge of scientific principles to large experience in the mechanical details of his pro- 
fession, his work commends itself not only to institutions seeking apparatus for lec- 
ture-room illustration, but to men of science pursuing original research. 

WILLIAM B. ROGERS. 



Amherst, June 5, 18G9. 
I have for many years been acquainted with Mr. E. S. Ritchie, as a designer and 
manufacturer of philosophical apparatus, and am prepared to speak in high terms of 
his intelligence and mechanical skill, as well as his courteous attention to those who 
apply to him for counsel or aid in his line of business. I am glad to look over the 
new catalogue of apparatus for schools, which Ritchie & Sons are just issuing, and to 
recommend it to the attention of all who wish to become purchasers. The improve- 
ments which they have made in many of the common philosophical instruments, have 
more than doubled their value. Teachers and experimenters may rely on the strict 
fidelity of the Messrs. Ritchie, in *egard to the quality and adaptedness of the articles 
which they furnish. 

E. S. SNELL, 
Prof, of Nat. Philosophy, Amherst College. 



East Hampton, June 5, 18G9. 
Mr. E. S. Ritchie has made a large amount of philosophical apparatus for me, at 
different times, and it has given me great satisfaction. In simplicity of design, accu- 
racy of operation, and perfection of workmanship, it is not surpassed. His Patent 
Air Pump is a very great improvement upon anything of the kind before constructed. 
It easily makes a vacuum nearly as complete as can be obtained by the laborious pro- 
cess of the mercury pump. The exhibition of the electric light in the vacua produced 
by it is equal to that in the best Geissler tubes. 

MARSHALL HENSHAW, 

President Williston Seminary. 



From Mr. John P. Gassiot, Vice-President of the Royal Society. 

London, March 7, 1859. 
Dear Sir : I have great pleasure in assuring you that the Induction Coil, which, 
through the introduction of my friend, Prof. William B. Rogers, you constructed for 
me, answers most admirably. With five of Grove's nitric acid battery cells I obtain 
eleven and a half inch sparks. The Vibrating Contact Breaker, which you subse- 
quently sent, has enabled me to repeat all the experiments with my Vacua Tubes, 
while the three divisions in your Coil affords facilities for varying the experiments in 
a manner that can be well appreciated by those who have worked with this apparatus. 

Believe me, dear sir, yours truly, 

JOHN P. GASSIOT. 
To Edward S. Ritchie, Boston, U. S. A. 



TESTIMONIALS. 45 

United States Military Academy, West Point, N. Y., June 4, 1869. 
The best portion of the apparatus in use in the Chemical Department at this institu- 
tion, has been made under the direction of Mr. E. S. Ritchie, of Boston. In all re- 
spects, everything- that has been received from him, whether ordered in person or by- 
letter, gives complete satisfaction. His Electrical and Pneumatical Instruments are 
of unequalled excellence. 

I have found Mr. Ritchie to be not only an entirely reliable gentleman, but one 
whose scientific attainments make him a valuable adviser. 

H. L. KENDRICK, 
Prof. Chemistry, tfc, U. S. Military Academy. 



Cambridge, Sept. 10, 1852. 
This may certify that Mr. E. S. Ritchie is well known to us as a manufacturer of 
•the best philosophical instruments used in academies and colleges. He is not content 
with supplying the usual apparatus found in all the catalogues, but he is ambitious to 
add to it new articles which illustrate fresh discoveries in science, or which excite a 
scientific curiosity. His integrity, his urbanity, and his skill all equally entitle him 
to the confidence of those who purchase or use philosophical apparatus. 

JOSEPH LOVERING. 
Hollis Prof, of Mathematics and Nat. Philosojjhy in Harvard College. 
JOSIAH P. COOKE, Jr., 
Erving Prof, of Chemistry and Mineralogy in Harvard College. 



Dartmouth College, Hanover, N. H., May 22, 1869. 
I take pleasure in bearing witness to the excellence of the Philosophical Apparatus 
manufactured by E. S. Ritchie & Sons. I have never found anything better in re- 
spect to accuracy of workmanship, and efficiency of operation. Their efforts to pro- 
mote science by being the first manufacturers in the country to construct the Induc- 
tion Coil, and the Holtz Electrical Machine, have deserved and obtained for them the 
regard of all American scientific men, and given them even a European reputation. 

C. A. YOUNG, 
Prof, of Nat. Philosophy and Astronomy. 



New York, Sept. 1, 1857. 
It is with great pleasure that I offer my testimony in favor of the excellent Philo- 
sophical Instruments constructed by Mr. E. S. Ritchie, of Boston. I have uniformly 
found them accurately and carefully made, durable and elegant. Mr. Ritchie seeks 
not alone to equal the best foreign instruments, but to surpass them, and to keep pace 
with the advancement of science. I have had repeated proofs of a characteristic pos- 
sessed by Mr. Ritchie, which I feel confident will be appreciated, viz., the sympathy 
and interest he manifests with the success of the experimenter, associated with a 
pride for his reputation, punctuality, and a determination to accomplish his aims. 

Respectfully submitted, 

R. OGDEN doremus, m. d., 

Prof. Chemistry New York Medical College, and College of Pharmacy. 



St. Louis, Mo., May 28, 1869. 
I am now using the Philosophical and Chemical Apparatus of E. S. Ritchie & Sons. 
Everything which I have seen of their manufacture has borne marks of mechanical 
skill, scientific knowledge, and the honesty which gives skill and knowledge their 
best results. 

C. S. PENNELL, 
Prin. of Mary Inst., a department of Washington University. 



46 TESTIMONIALS. 

University of Pennsylvania, Philadelphia, July 10, 1857. 
Having used with much satisfaction a variety of apparatus manufactured by Mr. 
E. S. Ritchie, I take great pleasure in bearing testimony to his ingenuity and scien- 
tific skill as a Philosophical Instrument maker. 

R. E. ROGERS, 
Prof, of Chemistry in the University of Pennsylvania. 



Andover, March 22, 1869. 
From time to time during the last ten years, I have had occasion to purchase appa- 
ratus of Mr. Ritchie, and have found every article satisfactory. Mr. Ritchie is pos- 
sessed of rare skill and ingenuity, and evidently takes pride in having every piece of 
apparatus in perfect order before it leaves his hands. 

WM. G. GOLDSMITH, 
Principal Punchard Free School. 



Yale College Laboratory, June 17, 1859. 

Scientific men in the United States, and teachers generally, are under many obliga- 
tions to Mr. Ritchie, not only for the general superiority of his apparatus, but espe- 
cially for his enlightened enterprise in undertaking many things for which we have 
before depended on Europe. 

I have found Mr. Ritchie ready at all times to undertake commissions out of the 
routine of his business, relying for his reward upon the reputation growing out of 
such a course. 

All the apparatus which I have had from Mr. Ritchie has been exceedingly well 
made, and has given me entire satisfaction. His stock of Physical and Chemical Ap- 
paratus is excellent. The pieces are well made, in good taste, and of reasonable price. 

B. SILLIMAN, Jr. 



Extract of Letter from Prof. Forbes, of the University of Edinburgh. 

Edinburgh, 16 July, 1858. 
My Dear Sir : . . . I have been highly pleased with the instrument. I have shown 
it in action to many scientific men, including Sir David Brewster. 

I remain, dear sir, yours faithfully, 

JAMES D. FORBES. 



Office of Sup't Public Sthools, Chicago, Feb. 15, 1859. 
The Board of Education of this city has recently purchased of E. S. Ritchie, of 
Boston, one thousand dollars' worth of apparatus, for the use of the Chicago High 
School. In thoroughness of workmanship and elegance of finish, it is unsurpassed 
by any apparatus that has fallen under my observation. Its performance is in the 
highest degree satisfactory. W. H. WELLS, 

Superintendent Public Schools. 



New England National Bank, Boston, June 4, 1869. 
Messrs. Edward S. Ritchie & Sons. 

Gentlemen : In my opinion, your house may be relied on for faithfully performing 
all its promises and obligations ; and this I declare, not only from a sufficient knowl- 
edge of it, but also from an intimate acquaintance with its members of longer stand- 
ing than the establishment. 

With esteem, yours truly, 

THOMAS LAMB, President. 



NEW AND VALUABLE 

TEXT-BOOKS IN PHYSICS 



GRAMMAR AND DISTRICT SCHOOLS, HIGH SCHOOLS, 
AND ACADEMIES, 



W. J. ROLFE and J. A. GILLET, 

TEACHERS IN THE HIGH SCHOOL, CAMBRIDGE, MASS. 



THE CAMBRIDGE COURSE IN PHYSICS 

IN THREE VOLUMES : 

I. CHEMISTRY, $2.00. 
II. NATURAL PHILOSOPHY, $2.00. 
III. ASTRONOMY, $2.00. 

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as to fill the space occupied by the Electricity in the old edition. 
New chapters on Crystallography and Organic Chemistry, from the 
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This edition (June, 1869) gives the nomenclature as adopted by the 
London Chemical Society, as taught at Harvard College, and as gen- 
erally used in scientific journals. 



The new edition of the "Astronomy " contains, in addition to the 
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an account of the Constellations, illustrated by 17 full-page Star Maps 
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These books are inductive in method, fresh in matter, simple in 
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the wants of our advanced Seminaries and Academies, and of those 
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THE HANDBOOK SERIES 

IN THREE VOLUMES : 

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II. HANDBOOK OF NATURAL PHILOSOPHY, $ 1.25. 
III. HANDBOOK OF THE STARS, $1.50. 

These books contain (aside from the Appendix) respectively 159, 
230, and 159 pages, in clear, open type, with no fate print, and they 
treat of all the topics usually included in school manuals of these 
sciences. The more theoretical portions of the subject are discussed 
briefly in Appendixes, and descriptions of apparatus and directions 
for performing experiments are added. Omitting the Appendixes, 
the books are not too difficult for the upper classes in Grammar and 
District Schools. With the Appendixes, they are exactly adapted to 
the wants of those High Schools and Academies which have not 
time for larger books. 

They are not abridgments of the larger works by the same authors, 
but are wholly new and independent books, differing from the others 
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* # * Circulars, containing notices and testimonials from eminent 
teachers, will be furnished on application. Copies for examination 
will be supplied at one half the advertised price, with twenty-five 
cents additional for postage. Special terms will be made for the 
introduction of any of the books. 

WOOLWORTH, AINSWORTH, & CO., 

117 Washington Street, Boston. 



